18. The system of claim 15 , wherein the search engine provides a corresponding plurality of rankings to the plurality of discussion thread web pages, the operations further comprising: displaying a plurality of links including the link to each of the plurality of discussion forums in a descending order of the plurality of rankings, such that a link to a discussion forum that includes a discussion thread web page with a highest ranking is displayed first.
15. A system comprising: one or more computers; and a computer-readable medium tangible encoding a computer program that is operable when executed to cause the one or more computers to perform operations comprising: receiving a request requesting a search of discussion forums and a search query; receiving information from a search engine identifying a plurality of resources that each satisfy the search query; identifying a plurality of discussion thread web pages among the plurality of resources that each satisfy the search query, wherein each discussion thread web page is in a particular discussion forum; grouping the discussion thread web pages into a plurality of discussion forums; extracting information about each of the plurality of discussion forums from the discussion thread web pages in the respective discussion forum; and providing the respective extracted information together with a link to each of the plurality of discussion forums to a user device for display to a user as part of a response to the search query.