6. The method of claim 1 , wherein the adapting comprises producing a plurality of context-specific relevance functions, wherein for each context-specific relevance function of the plurality of context-specific relevance functions, said each context-specific relevance function is adapted from the generic relevance function based on adaptation data that is based on a particular plurality of users and a specific context that indicates one or more characteristics of the particular plurality of users.
6. The method of claim 1 , wherein the adapting comprises producing a plurality of context-specific relevance functions, wherein for each context-specific relevance function of the plurality of context-specific relevance functions, said each context-specific relevance function is adapted from the generic relevance function based on adaptation data that is based on a particular plurality of users and a specific context that indicates one or more characteristics of the particular plurality of users. 7. The method of claim 6 , wherein the one or more characteristics include one or more of: websites visited by the particular plurality of users, geographic information of the particular plurality of users, demographic information of the particular plurality of users, tagging history of the particular plurality of users, search history of the particular plurality of users, or social network history of the particular plurality of users.