Anchor Text Awareness

According to an implementation consistent with the principles of the invention, information relating to a manner in which anchor text changes over time may be used to generate (or alter) a score associated with a document. For example, changes over time in anchor text associated with links to a document may be used as an indication that there has been an update or even a change of focus in the document.

Alternatively, if the content of a document changes such that it differs significantly from the anchor text associated with its back links, then the domain associated with the document may have changed significantly (completely) from a previous incarnation. This may occur when a domain expires and a different party purchases the domain. Because anchor text is often considered to be part of the document to which its associated link points, the domain may show up in search results for queries that are no longer on topic. This is an undesirable result.

One way to address this problem is to estimate the date that a domain changed its focus. This may be done by determining a date when the text of a document changes significantly or when the text of the anchor text changes significantly. All links and/or anchor text prior to that date may then be ignored or discounted.

The freshness of anchor text may also be used as a factor in scoring documents. The freshness of an anchor text may be determined, for example, by the date of appearance/change of the anchor text, the date of appearance/change of the link associated with the anchor text, and/or the date of appearance/change of the document to which the associated link points. The date of appearance/change of the document pointed to by the link may be a good indicator of the freshness of the anchor text based on the theory that good anchor text may go unchanged when a document gets updated if it is still relevant and good. In order to not update an anchor text's freshness from a minor edit of a tiny unrelated part of a document, each updated document may be tested for significant changes (e.g., changes to a large portion of the document or changes to many different portions of the document) and an anchor text's freshness may be updated (or not updated) accordingly.

Reference Document: http://appft1.uspto.gov