25. The computer-readable memory device of claim 23 , where the information the particular user includes one or more of: an Internet Protocol address associated with the particular user, cookie information associated with the user, a language associated with the particular user, geographical information associated with the user, prior queries provided by the particular user, or a period of time that the particular user provided the particular search query; and where the information regarding the particular search query includes one or more query terms included in the search query.
23. A computer-readable memory device to store data and computer-executable instructions, comprising: instructions to store log data associated with a plurality of searches of repositories based on search queries provided by users, each repository including at least one document; instructions to store the log data as triples of data (u, q, r), where; u refers to information regarding a user, of the users, that provided a particular search query, of the search queries, q refers to information regarding the particular search query, and r refers to information regarding a repository, of the repositories, from which search results were provided in response to the particular search query; instructions to determine a label for each of the triples of data (u, q, r), the label including information regarding whether the repository r includes information responsive to the search query q provided by the user u; instructions to receive a particular search query from a particular user; instructions to generate based on the triples of data (u, q, r) and the associated labels, scores for repositories, each of the generated scored being indicative of whether a particular repository, of the repositories, associated with the generated score, includes information responsive to the particular search query provided by the particular user, the scores being generated based on: a comparison of information about the particular search query and information about the search queries provided by the users, a comparison of information associated with the particular user and information about the plurality of users, and selections, based on the search queries, from the repositories; instructions to search the repositories, based on the particular search query, to identify, for each of the repositories, at least one set of search results; instructions to rank the repositories based on the scores; instructions to select at least one of the repositories based on the rankings; and instructions to generate a search result document based on the set of search results associated with the selected at least one of the two or more of the plurality of repositories.