Learning Linking Strategies From a Google Patent

By Jake Lowrey

A careful study of a recent patent application by Google results in a better understanding of what that particular search engine uses to determine the ranking of pages it returns in response to a user's query. Of course their filing does not detail how they make the determination, but the information is helpful nonetheless.

Google's patent application, No. 20070094254 titled "DOCUMENT SCORING BASED ON DOCUMENT INCEPTION DATE," was filed with the U.S. Patent and Trademark Office Nov. 20, 2006, and published by that office on April 26, 2007. The application itself is located at this Web address.

In a nutshell, the application states their "invention" scores the various documents on a variety of data including:

• Document Inception Date, when the document was first noticed
• Content Updates/Changes, freshness of the information
• Query Analysis, search terms used to find the document
• Link-Based Criteria, including number and dates of links
• Anchor Text
• Traffic
• User Behavior
• Domain-Related Information
• Ranking History
• User Maintained/Generated Data
• Unique Words, Bigrams, Phrases in Anchor Text
• Linkage of Independent Peers
• Document Topics
• Exemplary Processing

This article, however, will focus only on Google's linking criteria, which offers little, if anything, new, but does give webmasters valuable information when considering link campaigns for their Web sites.

Consider All Factors in Linking Stragegy

While the patent application states "one or more link-based factors may be used to generate (or alter) a score associated with a document," the wise webmaster will consider all the factors when planning linking strategy.

The first factor mentioned is the date of appearance or disappearance of links pointing to a document. [Note: See paragraph 0023 of the application for a complete definition of the term "document."] Using its own criteria, Google will determine the date when the link was found or when it disappeared then evaluate the time frame looking for a trend. Webmasters should also track this trend and be aware if it shows a steady increase or decrease in the number of links pointing to a document.

Google indicates they may determine the freshness, and thusly, the relevancy, of a document based on the trend it identifies. A more relevant document will show a steady increase in the number of links. Conversely, if the number of links pointing to a document is declining, Google will devalue that particular document.

Another factor considered by Google is the overall age of the links. The application gives this example: if two documents are first found on the same date, the one with the newest links will be considered more relevant. In addition, the "freshness" of a link may be weighted by Google based on the date of the link, any change in anchor text, or any change to the document containing the link. The application states:

The date of appearance/change of the document containing a link may be a better indicator of the freshness of the link based on the theory that a good link may go unchanged when a document gets updated if it is still relevant and good.

Now this is something the webmaster may have no control over if the link is coming from another Web site. However, it is good information of which to be aware. Bottom line: any linking strategy should be ongoing. Keep getting those links.

Trust, Authority Important Factors

Links are also evaluated on the level of trust or authority. The application singles out government documents as those that are given high trust. Again, something to which experienced webmasters are aware, but it bears repeating.

The age distribution of a document's links is one area where the discerning webmaster will pay particular attention. According to the patent:

... the dates that the links to a document were created may be determined and input to a function that determines the age distribution. It may be assumed that the age distribution of a stale document will be very different from the age distribution of a fresh document.

The very next paragraph in the application expands on this and warns against "spam," but at the same time says any large spike in the number of back links may indicate a topical event, specifically mentioning the CDC and an illness outbreak. The application does not say how Google will determine if a sudden increase is natural or the result of spamming, but it does leave the implication that they know when a webmaster is purchasing or exchanging links.

Bottom line: avoid purchasing a large number of links at one time and do not submit to a large number of free directories in a short time frame. Space those links out.

While the Google patent application may appear daunting in terms of linking, it does give webmasters an idea of how to work within their guidelines to achieve optimal placement for a Web site.

Jake Lowrey has communications experience as a news reporter, editor and public relations professional. Current assignments include writing for Team Link Network. He also blogs regularly at RavelBabel.com. You can reach him at jake@ravelbabel.com.