27. The method of claim 10 , where the search is performed based on a search query from the user.
10. A method performed by one or more computer systems, the method comprising: identifying a first set of documents associated with preferences of a user or a group of users, the first set of documents being identified from a query history or document browsing history associated with the user or the group of users; identifying a second set of documents that are different than the first set of documents; receiving information identifying a ranked set of search results associated with a search performed on a corpus of documents, for the user, where the ranked set of search results is ranked based on a link-based document ranking algorithm; identifying a third set of documents, each of the documents in the third set of documents being common to both the first set and the second set; identifying at least one document in the third set of documents that has a link to a particular document in the ranked set of search results; re-ranking the ranked set of search results based on one or more weights assigned to the at least one document, where the one or more weights are based on the preferences of the user or the group of users; and providing information associated with the re-ranked set of search result documents to the user.