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Content Update Ranking

The frequency and quantity of content updates may affect its scoring (section 46). The filing proposes the following formula:

U=f(UF, UA)

Where f is a formula such as a weighted sum, UF is the Update Frequency and UA is the Update Amount. The Update Frequence could be based on the time between udpates or number of updates over a given period. The Update Amount may be based on new outbound links or percentage of outbound links compared to the total associated with the document. As Google's PageRank algorithm is already link based this may provide a convenient heuristic where data storage restrictions prevent snapshots of the document from being stored. Techniques such as document hashes or storing small but important portions of the document (such as the most frequently occurring terms) may be used to monitor for updates. Google already has patents for generating similarity hashes for detecting near duplicate document content, a change in one of these hashes may indicate a fairly large document update.

It may also be based more traditional measures such as the amount of content visible to an end user that changes over a time period. Using "visible" content would avoid content spamming where pages are automatically updated with content hidden using CSS (style sheet) spam. Content deemed to be unimportant such as Javascript, comments, adverts, template, standard navigation elements, date and time tags would be discounted. More weight might be given to updates of certain HTML elements such as the title and anchor text.

The frequency and amount of change may be compared to see if it is decelerating or accelerating to influence scoring. An accelerating rate of change, even if relatively small, may score a document higher. For some queries more stable documents may be more relevant, in these cirumstances Google could calculate the average rate of change for a result set and favour documents that are below this average.

It seems that Google already does some of this analysis, the maxim of "update often" is already widely known amongst search engine optimizers and certainly seems to goven the frequency of visits by Google's search engine robots.

Content Update Ranking

See Also