Temporal Ranking of Search Engine Results

Existing search engines contain the picture of the Web from the past and their ranking algorithms are based on data crawled some time ago. However, a user requires not only relevant but also fresh information. We have developed a method for adjusting the ranking of search engine results from the point of view of page freshness and relevance. It uses an algorithm that postprocesses search engine results based on the changed contents of the pages. By analyzing archived versions of web pages we estimate temporal qualities of pages, that is, general freshness and relevance of the page to the query topic over certain time frames. For the top quality web pages, their content differences between past snapshots of the pages indexed by a search engine and their present versions are analyzed. Basing on these differences the algorithm assigns new ranks to the web pages without the need to maintain a constantly updated index of web documents.