1. A system comprising: one or more computers; and a computer-readable medium tangibly encoding a computer program operable when executed to cause the one or more computers to perform operations comprising: receiving information identifying a plurality of resources that have been identified by a search engine as satisfying a search query; determining that a first resource in the plurality of resources includes a post to a discussion forum; identifying one or more second resources that are each distinct from the first resource, that are each linked directly or indirectly to the first resource, and that each include one or more other posts to the discussion forum, and wherein the second resources include at least one resource that is not in the plurality of resources; extracting information about the discussion forum from the first resource and the one or more second resources including the at least one resource that is not in the plurality of resources; and providing the extracted information about the discussion forum together with a link to the first resource to a user device for display to a user as part of a response to the search query.