where either the content in a database or the terms being searched for by the community of users continually changes the methods for integrating new search session data should function in near realtime this necessitates an on line mechanism for learning query groups and relevance weights when this clustering involves a mixture model an on line variant of the em algorithm can be employed information about users as they search is distilled into an object known as a search session the pairing of a user 39 search term and the records they accessed while searching e g the query and complete path the present invention relies on two assumptions 1 search sessions can be obtained and 2 the information contained in a collection of search sessions can be used to assist in searching u201c in the future u201d in one embodiment of the invention the world wide web is searched by users for html documents relating to a given search term viewing the world wide web as a database the separate records or web pages are indexed by their urls for web searching a user 39 s search session consists of their search terms and urls of all the html pages they visited in response to their query several options are available for monitoring user activities on the world wide web in one embodiment we have made use of proxy server logs a proxy server is a computer that connects a community of users to the public internet it accesses content on.