.: Search Engine Ranking Factors

.: By Waqas Nasir ( a.k.a SEO Guru Pakistan)

Contents:

Introduction to Ranking Factors
Contributors
Most Important Factors
In-Document Factors Affecting Ranking (31)
Site Factors Affecting the Value of Hosted Documents (23)
Factors Affecting the Value of a Link (25)
URL, Technical, Hosting & Server Side Factors (12)
Detrimental Ranking Factors (12)

Introduction to Ranking Factors

This article contains a large list of the factors that can influence a web document's rank at the major search engines (Yahoo!, MSN, Google & AskJeeves) for a particular term or phrase. Although it is impossible to say for certain which of these items affects which search engine or how important the factors are individually, I've created an estimated ranking importance scale as indicated by the following symbols:

	Exceptional Importance These factors have primary influence in ranking search results at the major search engines.
	High Importance These factors have a high impact on modifying rankings of web documents in the SERPs.
	Moderate Importance These factors have a measurable level of affect on the rankings in the SERPs, but are not major contributors.
	Slight Importance These factors carry some impact on rankings and could be important when in a highly competitive area.
	Inconsequential Importance These factors are of low consequence in changing the ranking positions of a web document. They may have some effect in certain queries or documents.

For each factor, the 13 individuals (myself and 12 others in the field) voted on each factor's perceived importance. I then averaged these votes to come up with the scores you see listed next to the factors. In addition, the standard deviance (which measures how much fluctuation existed between votes) is also listed and a scale has been created to show if there was wide disagreement or general consensus on a factor's importance.

	Highly Disputed These factors have a wide variance of opinion on importance.
	Somewhat Disputed These factors have some dispute as to their importance.
	Average Agreement These factors have an average level of dispute/consensus.
	Some Consensus These factors have some consensus on importance levels.
	High Consensus These factors have a high level of consensus.

The factors listed herein provide a near-comprehensive list of factors which can positively or negatively influence the rank of a web document. If you have questions or would like to contribute additional ideas, please e-mail me.

List of Contributors

The following individuals made this project possible by submitting their opinions on each ranking factor, and adding comments where they felt it important. I have taken note of many of these comments in my description of the ranking factors and each score is representative of the group's overall opinions. Many thanks to:

Danny Sullivan	http://www.searchenginewatch.com/
Dan Thies	http://www.seoresearchlabs.com/
EGOL	http://www.seomoz.org/profile.php?action=view&username=EGOL
Graywolf	http://www.wolf-howl.com/
Jill Whalen	http://www.highrankings.com/
Donna Fontenot	http://www.seo-scoop.com/
Michael Martinez	http://www.michael-martinez.com/
Bill Slawski	http://www.cre8asiteforums.com/
Ammon Johns	http://www.webmarketingplus.co.uk/
Scottie Claiborne	http://www.successful-sites.com/
2K	http://www.2kmediat.com/kkmediat/eng/
Todd Malicoat	http://www.stuntdubl.com/
Rand Fishkin	My votes are also included in the avgs

Most Important Factors

The following are the top 10 ranked factors across the 5 categories:

Title Tag - 4.57
Anchor Text of Links - 4.46
Keyword Use in Document Text - 4.38
Accessibility of Document - 4.3
Links to Document from Site-Internal Pages - 4.15
Primary Subject Matter of Site - 4.00
External Links to Linking Pages - 3.92
Link Popularity of Site in Topical Community - 3.77
Global Link Popularity of Site - 3.69
Keyword Spamming - 3.69

In-Document (on-page) Factors Affecting Ranking:

The following factors are on-page items that affect the ranking directly by virtue of being a part of the indexed and retrieved document. Many of these factors will not apply universally to all documents, while others are standard.


	Factor Name	Description
	Title Tag Avg 4.57 \| Std. Dev. 1.12	Denoted by the <title> tags in HTML, this tag always shows at the top of a browser window and often appears in the SERPs as the title of the web page.
Bill Slawski In addition to the value of a title tag when a search engine determining what a page is about, people will often use the title of a page when choosing anchor text to link to the page. Michael Martinez Should be unique for each page on the site. Use for branding a company name as secondary content is okay. Scottie Claiborne Critical to ranking well. Todd Malicoat Also very important for those engines that track click through rates for natural SERPS.
	Keyword Use in Document Text Avg 4.38 \| Std. Dev. 1.00	The use of queried terms (the keywords users search for) appearing in the document text.
Bill Slawski While it isn't completely essential to have keywords appearing in the text of a document (search for "click here"), it certainly can help to have those words appear on the document. Michael Martinez Establish relevance through on-page factors where practical.
	Links to Document from Site-Internal Pages Avg 4.15 \| Std. Dev. 0.95	A specific page's importance in a site's overall architecture can be measured by the the importance and depth of the other pages on on the site that refer to the page in question. An internally well-linked to document is generally considered more important than an obscured or buried page.
Bill Slawski It can be tempting to relate number of links to a page with the number of valuable links to a page, but a page on a site linked to by the three most important pages on a site may be more important than another page linked to by hundreds of other pages. Danny Sullivan Disagree with this (RAND: Note, the above description has been changed since Danny's comment) Scottie Claiborne This is a factor the site owner has total control over and should utilize internal linking to enhance relevance. Todd Malicoat Easily the most underrated criteria by web developers everywhere. Getting the proper ratios of keyword anchor text with both internal and external links is crucial to good rankings.
	Uniqueness of Document Text Avg 3.38 \| Std. Dev. 0.92	A document's unique elements are what is generally looked at by the search engines and if the unique elements of a document (the body text or content) is an exact copy of another document (whether that document is on your site or on another), that page's value will often be deeply discounted or even removed from the listings.
Bill Slawski There may be more than one way of looking at duplicate content by the search engines. For instance, a mirror site may be ignored completely and not indexed, while very similar content may be indexed but filtered, and not served at the time of a query. Scottie Claiborne This may come into play in the future more than currently. Todd Malicoat Have thoroughly tested this, but my gut says if you beat the dupe filters you're probably going to be in okay shape.
	Related Term Use in Document Text Avg 3.31 \| Std. Dev. 1.06	Along with the actual targeted term/phrase, search engines examine all of the text in a document to determine if the other terms used are related and whether they give the subject of the document a specific slant as related to the primary subject.
Bill Slawski Global text similarities probably play a larger role here than the description you have implies, and similarities between documents can be helpful in defining the primary subject of a document. See Salton, et al, in Automatic structuring of text files. Dan Thies likely to have an influence, in link analysis, use of related terms may help w/ topical factors Scottie Claiborne It's a good idea and tends to happen naturally when writing Todd Malicoat I would almost argue that this is more important than exact terms in the document text, though both are very important
	External Links in Document Avg 3.08 \| Std. Dev. 1.14	The sites and pages linked to from a document. These may positively or negatively influence rankings based on the quality of the links, their relationship to the linking document and any existing relationships between the sites hosting the documents.
Michael Martinez Remove references to "quality". It's become an over-abused SEO buzzword. Scottie Claiborne We know analysis of external links happens when linking out. Todd Malicoat While relationships are important the actual ANCHOR TEXT is extremely important as well. Linking to documents with the anchor text of the phrases you are targeting for a specific page is quite helpful (though it may negatively impact visitor retention rate).
	Age of Document Avg 2.77 \| Std. Dev. 0.97	Nearly every document has an "inception date" calculated by a search engine as the first time the spider noticed the page or a link to the page. Older documents may be considered more "authoritative", "trusted" and "valuable" than new documents, particularly if they have continued to build links over a long period of time. New documents may be considered more "timely" or "relevant" to time-sensitive queries.
Danny Sullivan I think fresh documents these days might get a boost, but ironically old pages might also get a boost probably through looking at history of links. So no idea which way to go on this! DazzlinDonna Especially important to Google Scottie Claiborne I think the age of the domain may be more critical than the age of a specific document on that domain Todd Malicoat Definitely one of the hardest variables to manipulate. I think G is going overboard on it lately.
	Citation Links or Sources Avg 2.77 \| Std. Dev. 1.19	Citations (as footnotes or endontes in a research paper) could be links to additional info or mentions of publications, documents or papers from which information was drawn. This factor may be more prevalent in queries focused on academic or scholarly-type searches.
Scottie Claiborne I'm not sure the difference between this factor and the outgoing links described earlier. Todd Malicoat There's definitely different values to different links. This is a trend that will continue. May qualify as a 3 now, but I think link quality will fall under much heavier scrutiny, thus giving it a 4 in the future.
	Stemming & Plurality Evaluation Avg 2.39 \| Std. Dev. 0.74	Terms used on a page or in a query may be considered the same or only related by search engines. If a term is stemmed to its root form (i.e. financing & finance to financ) it could be that anchor text, queries, etc. containg that term would be equivalent & interchangeable.
Michael Martinez The meaning of "...would all provide equivalent value" is unclear. (RAND: Changed to make greater sense)
	Meta Description Tag Avg 2.39 \| Std. Dev. 1.21	The meta description tag is almost completely outdated in markup, but is still useful for describing your page accurately to the search engines. In some cases, the engines may even use this tag as the description of your site in the results page listings, giving you greater control over your content and message. It is questionable, however, that keyword use in this tag has any influence, whatsoever, in affecting the rankings.
Danny Sullivan but very important in terms of helping control a description, rather than ranking, in the right circumstances Michael Martinez Keyword use should be used where they stimulate user interest. Scottie Claiborne More important for getting people to click than for getting high rankings.
	High Level Authorship Marks Avg 2.38 \| Std. Dev. 1.21	These are structural signs that a piece of content is of great merit. Although we may not be aware of all the factors that fit into determining a document's quality through automated analysis, it is presumed by many that the major search engines have invested time and effort to find automated systems to measure a document's relative quality.
Danny Sullivan I think this is better said (RAND: Updated to make clearer) EGOL Examples would be a H1, H2, H3 hierarchy in headings/subheadings, ordered lists, quotations/citations, onpage anchor links.... USED IN CONCERT. If you want to see "high level authorship marks" look at this document... Todd Malicoat Hand edits are definitely a reality. Definitely important, but the prevalence will most likely always be fairly small compared to the overall size of the web due to it's sheer magnitude.
	Organization of Document Text Avg 2.31 \| Std. Dev. 1.26	In certain documents, particularly those with lengthy content and an obvious hierarchy or structure, the ordering of words, phrases, sentences and concepts can be taken into account by search engines.
Bill Slawski Sequence, proximity, and adjacency of words are important, but a global analysis of similar documents is probably a step taken long before an onpage analysis. EGOL Very little impact if we are talking about word order... but add a little HTML formatting such as headings, bold, ordered lists, onpage anchor links, and organization then becomes very important. Michael Martinez Organization that survives linearization is best. Scottie Claiborne I believe the page contents are analyzed as a document without regard to what is first vs what is last.
	Text in Alt/Img Title Tags Avg 2.23 \| Std. Dev. 0.97	The use of text in alt tags and image tags is figured into the overall text in a document, although it probably does not undergo the scrutiny of body text in terms of quality, grammar, reading level, etc. Both of these tags are more commonly used for targeting image searches at the engines, along with the filenames of the images shown.
DazzlinDonna Sometimes helpful for secondary terms Jill Whalen Very important for clickable images. Not so much for non-clickable ones. Scottie Claiborne Only in images that are links. Images that are not links typically show no change when adding alt text however for link images, it replaces the anchor text and as such, is very important. Todd Malicoat Alt text is actually important for using as repetitive anchor text for images. For instance the alt text of an image.
	Paragraph Headings Avg 2.23 \| Std. Dev. 1.12	Paragraph headings, either through Hx tags or simply through formatting may give detailed on-page emphasis to the topic of a page and demonstrate that multiple aspects of a topic are discussed - if the topics of these headings are diverse yet still clustered tightly around a theme, it may be beneficial.
Bill Slawski Attempting to understand a theme of a document (without looking at other documents) based upon paragraph headings, especially based upon layout without the use of heading elements, is probably not much of a relevance factor. DazzlinDonna Can be very important for less competitive terms.
	Variety & % of Content Changes Avg 2.23 \| Std. Dev. 1.19	Along with measuring historical and current rates of change, search engines watch for the amount of content that has changed in a document over the course of updates and which specific pieces of content on a web page have experienced change. For example, cosmetic changes (to color or fonts) may be ignored along with changes to every document on a site (during, for example, a template update). What search engines want to measure is documents that "keep up with the times" by adding new content and changing or removing old content that becomes invalid over time.
2K This is heavily linked to (internal and external) link data. Bill Slawski It's difficult to assign a value to this factor. Under the historic data patent from Google that this factor appears to be taken from, amount and type of change may be more important for some queries than others. For instance, a query for the "1998 superbowl"... Scottie Claiborne I don't see that this specifically affects rankings as much as it may change what the page ranks for. Any time you change page text, it will have an affect on the rankings.
	Document Language Avg 2.15 \| Std. Dev. 0.95	For obvious reasons, a document's language matching the query term and the user's location (by IP address or engine version used, i.e. google.de, yahoo.jp, etc.) is significant in making a document rank well.
Danny Sullivan much higher if you are using a country-specific service, otherwise, nope
	Keyword Use in URL Avg 2.15 \| Std. Dev. 1.02	Using the keyword term/phrase in the actual URL of the document may be assigned some weight by search engines, whether used in hyphenation or strung together.
Dan Thies people use the URL in links, don't they? DazzlinDonna Works better for non-Google search engines EGOL Probably does not help a lot if the KW is in your filename. However, IMO, owning the KW.com is kickass for rankings and SERP clickthrough. Michael Martinez Hyphenated keywords seem to work better. Scottie Claiborne Minor and only in play if people link to the page using the page URL. Todd Malicoat It is actually important by default. If someone links to your site using the URL, you have the keywords in anchor text rather than just a variable or arbitrary name.
	Meta Keywords Tag Avg 2.08 \| Std. Dev. 0.9	Although largely a remnant of the early days of web markup, the meta keywords tag is still used by search engines as a reference point for the terms targeted by the page. It can be of value to place common misspellings of your primary targets, if any, into this tag.
DazzlinDonna Can be more important in distinguishing a spammy site than anything else. Scottie Claiborne If it plays a role in ranking for misspellings, than it plays a role, period. You can't say it works for misspelled words but not for others. Personally, I don't believe it works for misspellings. I believe Google's habit of suggesting a correction for a misspelling or semantic analysis is more likely to be the source of "misspelled" traffic than including the misspellings in the meta keywords tag.
	Depth of Document in Site Avg 1.92 \| Std. Dev. 0.92	The depth of a document in a site's structure measures the minimum number of clicks (links that must be followed) in order to reach that document.
Bill Slawski A location metric (directory level depth) can be important to whether or not a page gets crawled, but it is possible for internal pages to rank higher than the home page of a site based upon the importance of links to that page. Dan Thies I don't like this description - depth within a site is not a "ranking factor" - link analysis is based on the relationship between all documents, not just those on the site - inbound links to an interior page, even if that page is 5 clicks from the home page. EGOL Deep pages can rank very well if lots of internal pages link to them, even at the same level, or if external links hit the page.
	Use of H1, Bold & Other Visual Tags Avg 1.92 \| Std. Dev. 1.44	Another pre-cursor of modern on-page optimization was the use of Hx, Bold, Strong and other accent tags to indicate the particular importance of a term or phrase to a search engine. This technique is not yet completely without merit, and it may be useful to highlight popular search terms for visitors to a site, hence the practice is still widespread. How search engines use this data is questionable, as it has been a source of so-called "over-optimization".
Bill Slawski There still is some merit to this approach, however, when you emphasize everything, you emphasize nothing. DazzlinDonna Great for less competitive terms, but may trigger over-optimization filters for competitive terms EGOL I think that this is still very important.... strong anchor text is powerful - especially for secondary keywords. Michael Martinez H1 and BOLD are still vital indicators of important factors. Scottie Claiborne Easy to abuse, I think the importance is downplayed, possibly when the amount of text on the page is compared to the percentage of "emphasized" text. Todd Malicoat Much less value now from abuse, but still more value than Meta tags.
	Use of In-Document Links & Anchors Avg 1.85 \| Std. Dev. 1.10	Search engines may use named anchor data, particularly in longer documents or those carrying a consistent structure (as with many Wikipedia entries) to help with classification and ranking.
EGOL Great for KW reach and can boost rankings on secondary terms. e.g. RED widgets vs widgets
	Rate of Updates to Document Avg 1.85 \| Std. Dev. 1.10	Over time, a document may experience changes in content or links and search engines, who regularly re-spider pages (how frequently depends on both their perceived importance and their rate of changes) may place value on regularly updated pages. The rate of updates is not simply a measure of how often change occurs, but a tabulation of all changes to a document historically.
Bill Slawski It's difficult to lump all of these factors together, and by itself this rate of updates may not be that large a factor. Some documents retain their value while not changing, especially important historical documents, while others derive their value from frequent updates. EGOL Might give you a small and temporary "bump". Todd Malicoat This is relative to the query itself I think, as searches are categorized by type, freshness may be a very positive factor for a site ranking for news type queries, whereas staleness may be only a marginal factor for a page ranking for a history question.
	Document Length Avg 1.54 \| Std. Dev. 0.63	The length or size of a document, both in terms of KB size and number of words or characters may be used by the search engines to influence rankings. In some instances, search engines may guess that a shorter or succinct document is preferred based on the query, while in other instances, a longer, more detailed article may be desirable. Document length and size does not have a optimum level, but can be used by search engines in the rankings.
EGOL I don't think that this counts for a lot because I see pages with a couple of sentences or less at TopSERP for lots of moderate difficulty terms. Todd Malicoat Probably important but highly query relative in my mind, and thus very difficult to make observations about.
	Document Type Avg 1.54 \| Std. Dev. 0.84	Document types such as .pdf, .doc, .txt and others may be included or given more or less favorable ranking treatment based on the query and a search engine's perception of what the user is seeking. When searching for research papers, for example, PDF and MS Word documents may be more desirable.
No Comments
	Quality of Document Text Avg 1.46 \| Std. Dev. 0.75	Although highly subjective, there have been many proposed methods for automatically measuring document text quality, most frequently by measuring (in large quantity) a variety of high quality documents against low ones to find natural indicators of one or the other, then using those to attempt to classify future documents. Whether and how soon this could impact rankings is debatable.
No Comments
	W3C Validation Avg 1.46 \| Std. Dev. 0.93	The W3C organization of web standards issues requirements for validation. These standards are used by many websites to construct "proper" markup in the HTML document type of their choice. Whether search engines measure proper validation is up for debate, but could be considered a ranking factor.
Bill Slawski Validation by itself is unlikely to be a ranking factor, however, a valid, error free page following standards may rank better than one that isn't because a defined DTD and charset may reduce the possibility of errors in interpreting a page. Dan Thies Does any search engine's home page validate yet? Danny Sullivan i wish you had a zero, because that's what I'd be voting here. DazzlinDonna Only useful in making sure spiders can index the page. May have some merit with MSN. EGOL Has anybody tested this to see. Sounds like something very easy to test and settle all questions. Todd Malicoat Would be pretty hard to do from an SE standpoint, but would logically be a factor.
	Grammar Use in Document Text Avg 1.46 \| Std. Dev. 1.08	Grammar use by the search engines is questionable, but it has been noted by academic papers and research as a possible method to determine the relative quality of a document. Those documents which take care in preserving grammatical guidelines (my supposition is that these will not be strict) could be rewarded with greater weight in the rankings.
2K Basic markov chaining laws apply here. Bill Slawski A sentence may be semantically correct, and completely meaningless. Michael Martinez Identifiable grammatical and idiomatic structures distinguish natural content from spam. Scottie Claiborne It's possible that it helps. I've not tested this theory. It's definitely critical to conversions.
	Internal Links in Document Avg 1.3 \| Std. Dev. 0.6	The relevant internal documents pointed to by a page may help to indicate to a search engine the subject of the page and the general subject of the content therein. Persitent navigation links (those in a menu or footer nav) will generally be ignored.
Bill Slawski Persistent internal links do have the potential to make a page appear relevant for a particular query, especially if there is a correlation between the anchor text within those and such things as page titles, and words upon the pages. Dan Thies once again, you're mixing two things, and making an assertion (nav links will be ignored) - what am I rating? DazzlinDonna Can be more important for less competitive terms EGOL Small for your main term of attack but this can greatly increase the keyword reach of your document (get you ranked for lots of related terms)! Jill Whalen no idea what you mean here Scottie Claiborne Goes back to internal linking question. Todd Malicoat I don't think the anchor text of navigation links is always ignored. Perhaps the passing value, but the actual text still plays a role I think.
	Spelling Accuracy in Document Text Avg 1.23 \| Std. Dev. 0.58	As with grammar, spelling accuracy may be measured by the search engines to determine quality. This factor will most likely be applied relative to the query entered so that sites in particular categories, such as humor, culture-specific, artistic and other areas where misspellings are intentional do not get filtered.
2K Basic markov chaining laws apply here, too. Scottie Claiborne Not for SEO. but for professionalism and conversions
	Stopword Frequency Avg 1.23 \| Std. Dev. 0.58	Stopwords (common non-noun or descriptive words such as the, it, can, been, where, how, up, etc.) are measured by search engines to determine the style of writing the content of a document is using. A high frequency can mean a lengthier, article style of writing, while very low frequency typically indicates more bullet points and promotional writing (non-paragraph form). This would most likely be a query dependent factor - affecting those searches where one type of writing was clearly preferable to another.
2K Depends on language used. Bill Slawski "To be or not to be" holds quite a lot of meaning, regardless of the fact that it is completely constructed of stopwords. Scottie Claiborne Again, not as a ranking criteria but important for natural language overall. This isn't something that has to be
	Reading Level of Document Text Avg 1.08 \| Std. Dev. 0.27	Reading level is typically calculated by measuring the words in a document and measuring their syllables or obscurity against wordlists from educational guidelines. Thus, complex documents might be considered to be at a 12th or 13th grade level (high school senior or college freshman in the US) while low-level, simplistic documents would be at a 5th or 6th grade reading level. A higher or lower level does not necessarily indicate a better result, but based on search terms, it could be more or less likely that a higher or lower reading level document would be preferable.
Dan Thies I'm tempted to vote for this factor to trick people into writing better copy. Danny Sullivan i don't know any search engine doing something like this Todd Malicoat I think this will actually become increasingly important as SE's try to further remedy the problems associated with duplicate content.

Site Factors Affecting the Value of Hosted Documents:

The following factors affect all documents hosted at a particular website. These factors influence the overall strength and focus of the site where documents are hosted, thereby affecting any page at the site.


	Factor Name	Description
	Primary Subject Matter of Site Avg 4.00 \| Std. Dev. 1.11	A website's primary topic (as determined through analysis of the content of its hosted documents) may influence how well it is able to rank pages on similar, corresponding or off-topic subjects. If a site is particularly focused in one niche or another (from finance to politics to restaurants), documents hosted at that site on specific subjects encompassed by the broader topic may have a better chance of ranking well. There are also many sites on topics like news or general information distribution (e.g. CNN.com, Topix.net, etc.) that encompass all or many subjects equally and may be able to rank documents for a wide variety of topics.
EGOL This might be one reason that some of the specialty sites rank higher than Wikipedia. Don't know for sure but this is my analysis.
	Link Popularity of Site in Topical Community Avg 3.77 \| Std. Dev. 1.48	Topical communities are measured by the search engines as groups of websites who interlink to and with one another frequently and carry a similar topic or theme. Since topical communities are relevant and "on-topic", the links from them carry great weight. A site that is included in a topical community by way of links from many other members may be considered more relevant and authoritative on the community's subject matter.
No Comments
	Global Link Popularity of Site Avg 3.69 \| Std. Dev. 1.49	Global link popularity simply measures the importance of all the links to a unique domain, with more links from more important sites (relative to their own link popularity) typically having stronger influence.
EGOL This is what makes an "authority site"..... and I am suspicious that if "global" means "worldwide" also then you go up to another level... such as links from other countries and languages .ca, .jp .uk .etc Michael Martinez Appears to be relevant for standalone domains and sub-domains.
	Internal Link Structure Avg 3.23 \| Std. Dev. 1.12	A site's internal link structure may influence the rankings of its pages by virtue of its organization. Search engines and visitors alike typically expect a persistent set of navigation elements as well as a hierarchy from broad subject matter to narrow. Sites exhibiting these types of linking structures may be rewarded with better rankings.
2K perfect tool for document popularity control Dan Thies Sites that point more links at important pages magically discover that those important pages get more clicks from visitors and rank better. EGOL I think that the benefit here is in quantity of internal backlinks.
	Rate of New Incoming Links to Site Avg 3.08 \| Std. Dev. 0.73	The links pointing to a document over time may be measured and have data extrapolated by the search engines to help the determine the legitimacy and value of new links. This may in turn affect the rankings of any documents hosted at the site, whether they are directly receiving external, inbound links or not.
Jill Whalen Only in terms of those who try to artificially inflate their links. Todd Malicoat Highly relative to query type.
	Topical Relevance of Incoming Links to Site Avg 3.08 \| Std. Dev. 1.21	The links pointing to a site may be considered relevant or off-topic. In the latter case, their value may be discounted. This could be determined by looking at what other links are being pointed to on the linking pages, the subject matter of the linking site/page and the relationship between the two sites. If many relevant, on-topic links from relevant, on-topic sites point to the website, documents there could rank higher as a result.
Danny Sullivan Though I'd say link to a page, rather than to a site Todd Malicoat It will be a 4 soon, though probably a 3 now. Improving the topical nature of links is most likely one of the strongest focuses by engineers currently I would assume.
	Anchor Text of Incoming Links to Site Avg 3.08 \| Std. Dev. 1.59	In determining a site's subject matter, both the text of the site's hosted documents and the text of links pointing to the site may be contributing factors. If many links point to a site with anchor text that is "on-topic" for a document hosted at the site, that document may have a better chance of ranking well for the query.
Bill Slawski Site or document? (Rand: Anchor text of all links to a site would impact the rankings of documents hosted there)
	Age of Site Avg 2.92 \| Std. Dev. 1.14	A site's age may influence the value and trust placed upon documents hosted there by search engines. Older sites are generally considered more trustworthy than newer sites as they have established a record of legitimacy.
Ammon Johns The age of links, and that links continue to grow, is important. The age of a document is not. DazzlinDonna Especially important for Google.
	Site Language Avg 2.62 \| Std. Dev. 0.92	The language focus of documents at a website may make documents hosted there rank higher or lower for language-specific or engine specific queries (i.e. Google.de, Yahoo.jp, etc.).
No Comments
	Historical User-Action Metrics Related to Site Avg 2.62 \| Std. Dev. 1.00	The primary user-action in the SERPs would be a click-through to a search result. If a site receives a high click-through rate in the natural results and few searchers return to the engine immediately to select an alternate result or conduct a new search, the website and any hosted documents may benefit.
Dan Thies What do YOU think "user acceptance" means? EGOL If they are not using this then they need to have their heads examined!
	Rate of Expiring/ Removed Links to Site Avg 2.31 \| Std. Dev. 0.99	As links are found by the search engines pointing to a site and others that are removed disappear from the cached pages, data about link fluctuation, generation and dissipation can be stored in the search engines' repositories. This data may then be used to analyze future activity, make predictions, compare against other sites and find abnormalities. Sites that receive very few permanent links may be ranked lower than those whose links remain. Other websites where link stagnation is fast may be compared against others in the industry to see if this phenomenon is normal. All of these factors of link gain and loss over time may result in higher or lower rankings for hosted documents.
Todd Malicoat This will probably become more important as "advertising links" are targeted.
	Domain Extension Avg 2.31 \| Std. Dev. 1.20	.com, .net, .biz are all commercial extensions, freely available to anyone. But, domains like .gov, .mil or .edu may only be purchased and operated by those with special privileges. As such, a domain carrying one of these extensions may be considered more "trustworthy" and therefore receive a boost in ranking.
2K country domains affect serps way too much! Dan Thies Pure and utter rubbish nonsense jibba-jabba... Michael Martinez The self-policing of the .org top-level domain may explain its apparent quality boost. Strict requirements for .edu, .gov, and .mil may explain quality boost for those TLDs.
	Semantic Connections of Hosted Documents Avg 2.15 \| Std. Dev. 1.17	The semantic connections between documents hosted on a website may influence their respective rankings. If, for example, a high correlation occurs between topics or terms in many documents on a site, that site may be perceived by a search engine to be particularly on-topic for a subject and thus have its documents rank better.
2K will be a big player in future. Dan Thies You keep saying "the site may be perceived" when this isn't necessarily how it works. TSPR accomplishes this without having a concept of a "website."
	Keyword Use in Domain Name Avg 2.08 \| Std. Dev. 1.14	Search engine may consider the value of a keyword or related term/phrase in the actual domain name of the site. Relevant terms/phrases would thereby benefit sites with those terms/phrases in their name.
Dan Thies People use the URL in links, right? EGOL Yes... but more important... owning the KW.com attracts natural links like bugs to a Georgia porchlight.
	# of Hosted Documents Avg 2.00 \| Std. Dev. 1.41	The size of a website as measured by the number of documents hosted on the site may raise or lower rankings depending on whether a search engine has a query-dependent or universal preference for larger/smaller sites.
2K not the number, but the linking structure.... Ammon Johns Where this increases link counts it positively affects the site. Where it does not, it does not. Dan Thies larger sites have more of a presence not because search engines "like" larger sites, but because they have more love to spread around EGOL I don't think that this in itself gets you a ranking boost. But it gets you more internal backlinks. Scottie Claiborne I don't think the numbers of pages in a site matters as much as the impact of the additional internal links created by those pages.
	Historical Rankings of Site in SERPs Avg 1.92 \| Std. Dev. 0.73	A site's rankings(and its hosted documents') in the search results over time may be used by a search engine to influence ranking ability up or down over new documents or documents suddenly ranking much better than before. This is most often used in cases where large jumps in rankings over a short period are seen and the engine wants to investigate whether that jump was natural or the result of spamming, but other uses for the data are also possible.
Ammon Johns A site that has been found over time will usually attract more links than a site which has not. DazzlinDonna Especially used by Google.
	Hyphens in Domain Name Avg 1.92 \| Std. Dev. 0.73	It has been noted on several occasions that 2 or more hyphens in a domain name may indicate a lower-quality or spam-ridden site. This data may be used by search engines to reduce the rankings of a site or its hosted documents.
Dan Thies Overhyphenation, sure, why not. Show me ONE quality site with 5 hyphens in the domain name. Danny Sullivan So I think hyphens are a BAD thing and may be fairly important in marking down. Others think they are good. I assume those who think they are good will mark this as a LOW factor.
	Existence of Sitemap Page on Site Avg 1.92 \| Std. Dev. 1.07	A sitemap page, particularly one noted as such via anchor text or title may boost the crawling speed and thus ranking effectiveness of documents at a website.
Dan Thies Again, you add a little extra speculation when it's not needed. The words "particularly one noted" tempt me to rate this as a 1, but I'm ignoring those words to give proper respect to sitemaps. Scottie Claiborne Only because it adds an additional keyword rich internal link, not because there is any sort of magic in a sitemap Todd Malicoat Adding a sitemap to sites that DON'T have one has always produced very tangible results from my experience.
	Membership in Sitemaps/Paid Inclusion Programs Avg 1.77 \| Std. Dev. 0.89	Using programs like Google's Sitemaps or Yahoo!'s paid inclusion supposedly do not influence search engine rankings, but they do influence the crawl speed and depth, giving your documents a better chance of receiving boosts for fresh content or timely, relevant content to a searcher's query.
Dan Thies Y! is a double-edged sword. It's not really about better rankings, it's the speed with which testing can be completed. Todd Malicoat More important for Yahoo, with Google it just to assist in getting all pages IN the index.
	Rate of Document Additions/Change Avg 1.615 \| Std. Dev. 0.74	A site's overall rate of document flux (new documents added and older ones removed) may impact the rankings of documents hosted at the website. Over time, this changing acceleration or deceleration may be used by the search engines to positively or negatively affect the rankings of particular documents based on their own ages in comparison to the data about other documents at the site.
Ammon Johns Frequently changing documents may gain more links through updates than a more static, less changeable document. EGOL I don't think that this is extremely important. If it was then EBay should hold TopSERPs everywhere! Todd Malicoat Another highly relative variable which is stronger/ weaker based upon the type of query.
	Use of re-direction directives Avg 1.46 \| Std. Dev. 0.75	The use of re-direction directives such as 301 (permanent) and 302 (temporary), may impact ranking results based on their frequency of use, the source and target. websites which have recently been re-directed from another site may have lower trust placed on them by search engines.
Dan Thies AFAICT... it's a crapshoot. Y has used assumptions about redirection in the past, but they seem to have listened to reason. Google just wants the world to follow the spec. SEOMoz's problems were more likely due to having a lot of documents added all at once. Todd Malicoat Can potentially have LARGE impacts on rankings, but in itself not a huge variable if done correctly.
	Size of Hosted Documents Avg 1.31 \| Std. Dev. 0.61	The relative size of hosted documents at a website may help a search engine predict the scope and type of site - for example, if a large number of documents are extremely lengthy research work, it could be used to influence rankings for those types of queries at the engine.
2K very small (<10 words) documents do seem to be outranked in all cases.
	Shifts in Rate of Change to Hosted Documents Avg 1.15 \| Std. Dev. 0.53	The average rate of changes to all documents hosted on the website may be used to construct information about the changes and updates most recently found on the documents. THis may help certain documents rank better or worse than others against one another or external documents.
Dan Thies It's going to be important, but the engines have to figure out what to do with it - G has patented every possible interpretation, pro and con.

Factors Affecting the Value of a Link:

These factors influence the power, relevance and rank boosting effect a link carries with it when pointing to a particular document. Note that all links, in addition to being influenced by these factors, are affected by many of the site and page factors above. These are mentioned below where they are of particular importance.


	Factor Name	Description
	Anchor Text of Link Avg 4.46 \| Std. Dev. 0.93	The phrasing, terms, order and length of a link's anchor text is one of the largest factors taken into account by the major search engines for ranking. Specific anchor text links help a site to rank better for that particular term/phrase at the search engines.
No Comments
	External Links to Linking Page Avg 3.92 \| Std. Dev. 0.92	The external links that point to a document can have a strong effect on the power and relevancy that links from that document to other documents carry.
No Comments
	Global Popularity of Site Avg 3.85 \| Std. Dev. 1.41	The global link popularity of a website affects the value of all the links in hosted documents on the site. Highly linked to sites will provide more value in their links than sites whose link popularity is low.
Dan Thies oversimplification is rampant in this section... EGOL This is what makes an "authority site"..... and I am suspicious that if "global" means "worldwide" also then you go up to another level... such as links from other countries and languages .ca, .jp .uk .etc
	Popularity of Site in Topical Community Avg 3.77 \| Std. Dev. 1.25	As mentioned before, topical communities created by sites on a specific subject linking back and forth with one another can influence the rankings of a document included in this "community" positively. Likewise, links from these "in" documents/sites can carry additional weight with search engines. A link from a site/page that is particularly well linked to within its own topical community may be of especially high value.
Dan Thies It's probably not the site, more likely it's the page, except maybe @ Ask. Scottie Claiborne Matters more on some engines than others.
	Text Directly Surrounding the Link Avg 3.54 \| Std. Dev. 0.84	The greatest text analysis for a link, next to the actual anchor text, is the text directly surrounding that link. This is more true for links embedded in content than those which float outside primary content areas. It often includes, in the case of lists of links, the description about the linked to document/site.
No Comments
	Anchor Text of All Links to Site/Document Avg 3.46 \| Std. Dev. 1.28	The anchor text of links pointing to a document could influence its relevance and may directly carry the value of those anchor text links over to the pages and sites it points to.
No Comments
	Location of Linking Page in Site Structure Avg 3.31 \| Std. Dev. 1.07	The location of the linking page in the website's site architecture can impact its effect. For example, a link that is buried 4-5 levels away from the home page may not be as valuable as a link prominently placed on the home page or a page directly linked to it.
EGOL Other factors override this easily.
	Affiliations of Linking Site with Target Site Avg 3.00 \| Std. Dev. 0.56	Affiliations between websites via reciprocal linking, shared hosting, shared domain registration affiliations or other methods may impact the value of a link from any documents at one site to the other (typically by dampening their effectiveness). This is done to minimize so-called "incestual" linking from sites owned or controlled by the same entity or from sites whose links are not given out of editorial "respect".
2K depends on language /country once again... Dan Thies You're overloading this factor - reciprocal linking is not the same as RED FLAG linking, like sharing the same IP address with everyone who links to you. EGOL These are the types of inbound links that can hurt you if done to excess.
	Existence of Rel=Nofollow tag Avg 3.00 \| Std. Dev. 1.36	The "nofollow" tag indicates to a search engine that the link to the tag is applied to is not "vouched for" by the creators of the site. Typically, this means that the link was not editorially approved and may, therefore, have been created by a site visitor, or even an automated spam program.
Dan Thies True, but how is this supposed to influence rankings, unless you're texas hold'em guy? DazzlinDonna If it does exist, the link is essentially worthless.
	Text on Linking Page Avg 2.92 \| Std. Dev. 0.83	The quality and features that can affect the text analysis of a page also influence the value of links from that page, both in terms of weight and relevance to a particular subject, phrase or term.
No Comments
	Semantic Relationship of Linking Page Avg 2.92 \| Std. Dev. 0.83	The relationships of the topics and text content of the linking page and the target page are considered when determining the relevancy and value of a link.
Dan Thies this one you may have under-simplified. :D
	Age of Link Avg 2.85 \| Std. Dev. 1.03	A link's historical presence on a document may be considered when analyzing its value. Older links are typically thought to provide greater value than newer links.
Ammon Johns Older links will suggest past relevance as many stories and articles are temporal, and technically expire. Newer links indicate current trends. Dan Thies The age of links is a factor. but what am I rating? "Older links are typically thought to provide greater value than newer links" or newer links may indicate an important resource, or...
	Implicit Trust of Site Avg 2.77 \| Std. Dev. 1.12	There is speculation that some websites have gained the implicit trust of search engines. Educated guesses on their identities range from places like CNN.com to DMOZ.org to Whitehouse.gov, all in varying degrees, and all purely hypothetical, unknown in truth to all but a few engineers. Links from these sites may carry special weight and rank boosting power, although it will probably never be possible for SEOs to correctly identify or quantify them.
Dan Thies I don't buy this, all the "example" sites have plenty of authority because they're authorities... but there is "explicit mistrust" of certain sites. Did WSJ linking to SEOBook.com mean more than me linking to it? Not likely.
	Additional External or Internal Links on Page Avg 2.69 \| Std. Dev. 1.14	The internal and external links on a document may influence the value of new outgoing links on that page, either positively or negatively, based on both quality of the documents being linked to and their subject matter.
Dan Thies yes, some of this is part of the PageRank algo... add a link, the rest are diluted
	Shared IP Address or C-Block Address Avg 2.62 \| Std. Dev. 0.92	If a site shares an IP address or a C-Block of IP addresses with the target linked-to site, a document's link may be devalued partially or entirely.
Dan Thies assuming we ignore the tremendous value of internal links within a site, and pretend that there's something wrong with having >1 domain
	Related Term Use in Linking Page Avg 2.54 \| Std. Dev. 0.63	If on-topic, related terms are used with frequency on the linking page, this can indicate to a search engine that the link carries higher relevancy to the page's text. Likewise, if a link is entirely off-topic as compared to a page's content, that link may carry less weight.
Ammon Johns This may already be counted partially in the text near links part.
	Rate of All External Links to Site/Document Avg 2.38 \| Std. Dev. 0.92	A linking document's rate of external links that point to it or link to the hosting site can strongly influence the power a link from that document carries, both positively and negatively.
Dan Thies what is the "rate of external links?" how fast they move, how many there are, how it changes over time? Michael Martinez Not clear on what you mean by "rate". (RAND: I'm referring to both the number over time and the acceleration or deceleration of that rate - the 'calculus' of the measurements)
	Domain Extension Avg 2.38 \| Std. Dev. 1.39	The extension of a site may impact the value of its links - .edu, .gov & .mil have all been surmised to carry stronger weight in their links than ordinary commercial documents (.com, .biz, .net, etc.).
Dan Thies Utter nonsense, well, except for commercial sites that use .org names - that's definitely screwy and no doubt will be deal with harshly. 8) Scottie Claiborne I do believe some tld's have more impact. Todd Malicoat I'll take three strong .edu's vs. 6 strong .coms any day:)
	Link Relationships Between Sites Avg 2.31 \| Std. Dev. 0.91	If two websites link to one another's documents, subsequent links between the two or to a third party site which the other has already linked to may reduce the value of the link partially or fully.
2K I doubt, because this is natural in topical communities. Ammon Johns Creating 'pockets' of links, cyclic linking structures, can make the link structure look artificially inflated. EGOL Sites of the highest quality link to each other all of the time.
	Existence of Link on Other Pages of Site Avg 2.15 \| Std. Dev. 0.95	If a link to a website's documents already exists on other documents of the linking site, further links from other pages may not be as valuable or may be discounted entirely.
Dan Thies Why would the engines do this? Links to a page from multiple pages implies that the page is more important, additional links allows for broader keyword coverage in link text Scottie Claiborne Not sure - are you talking about sitewide links from external sites? Assuming this to be true. (RAND: Sitewides or simply multiples)
	Rate of Content Changes to Linking Page Avg 2.15 \| Std. Dev. 1.10	The rate of new content and content updates on a document may affect the value of links they pass. Freshly or frequently updated documents may provide greater value than older documents, or older documents may offer more stable, trustworthy links, depending on how the search engines view this data.
Ammon Johns As before, changeable documents may gain greater link popularity thereby, which has a direct effect. Dan Thies Are you going to add "broken links on the linking page" to this some day?
	Location of Link on Page Avg 2.15 \| Std. Dev. 1.35	A link that is visually closer to the top of a long page may be ascribed greater value depending on the format of the page and the visual presence of other links.
2K not valid question at the moment... should be "location of link in code" Ammon Johns Block level analysis, or indications that a link is in the footer will devalue the link considerably. Dan Thies oversimplified, but probably true with some caveats DazzlinDonna May be more important with MSN Todd Malicoat Becoming increasingly important I think, though probably not yet highly influential.
	Updates/Changes to Link Avg 2.15 \| Std. Dev. 1.35	The updates or changes to a link itself, including title, anchor text, the link's location in a document or the document it points to may be factors influencing its weight and relevance.
Dan Thies yeah... switching a link often enough can probably make it nearly useless @ Google, but Y & M both seem to love DigitalPoint link boxes Scottie Claiborne This question is a little misleading- changing the anchor text is important, but I don't think it's position on the page matters, personally Todd Malicoat "link shadow" is an interesting variable...how long after a link is removed does it retain it's value.
	Visual Tags Affecting Link Text Avg 1.69 \| Std. Dev. 1.14	Bold, Hx or other tags ascribing greater visual import to a link may be used to determine if a link's value should be greater than other links on the page.
Scottie Claiborne Possibly true. I believe it would depend on the overall markup of the page.
	Link Title Avg 1.54 \| Std. Dev. 1.08	The link title attribute may be used by some search engines as a factor in rating a link's relevance or effect. This factor may be more relevant if the anchor text is nonexistent or without meaning (i.e. an arrow -> or "click here").
Dan Thies Link titles are not visible to users Jill Whalen These don't appear to be indexed by engines.

URL, Technical, Hosting & Server Side Factors:

These factors affect a document's rankings by virtue of their affect on technical, spidering/indexing or trust areas of the search engines' rankings.


	Factor Name	Description
	Accessibility of Document Avg 4.31 \| Std. Dev. 1.32	Inaccessible documents could be due to 404 errors, server mishaps, plug-in requirements or other technical issues. Accessibility can also be compromised by using URL re-directs that search engine spiders cannot follow, hiding content behind select forms, javascript or other hard-to-spider forms of navigation.
Ammon Johns Depends on the issue in question. Danny Sullivan not a ranking issue; an indexing issue, same for most of rest below Scottie Claiborne If they can't access them... they can't index them. Todd Malicoat If they can't spider you, you can't rank.
	Session ID Variables Avg 3.62 \| Std. Dev. 1.08	Session variables can produce hazardous search rankings as duplicates of a URL's contents are indexed hundreds or thousands of times, dilutin