• Inception date corresponding to the document. Inception is the time when the search engine discovers the document or a link to the document. This points to the much talked about sandbox theory, according to which new sites are listed in Google only after a predetermined amount of time has elapsed. This also helps in fighting spam as sites cannot set up link farms pointing to themselves and shoot up in the rankings over night.




• The one interesting thing to note here is that a document's ranking are also based upon how much it has been selected previously on being listed in the search result pages. This gives an additional human filter to the ranking process.




• Additionally, Google also lists the amount of time a user spends accessing the document shown up in the search results as a factor. However, it's difficult to deduce how Google would come to know of that time. Most likely this might be reported by the Google Toolbar, if at all it is included in the search algorithm.




• Analyzing a traffic pattern associated with the document to identify changes in the traffic pattern over time. Little is known about how this could affect the search results.




• Determining whether user maintained or generated data indicates that the document is of interest to a user. The data here relates to at least one of favorites lists, bookmarks, temporary internet files, and cache files. This has been an integral element of some of the so called human search engines like Furl.net andSpurl.net for quite some time. There is little confirmation about whether this is already included in the Google algorithm or not.

It seems unlikely that all of the above are being implemented in the current Google algorithm.Most probably Google seems to be going a bit protectionist about the way search technology evolves. The Google engineers seem to have done a pretty good job in thinking about every which way a search could be based upon ;).