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; identifying a first resource in the plurality of resources as including a post to a discussion forum; identifying one or more second resources that are each distinct from the first resource, each second resource being linked directly or indirectly to the first resource, each second resource including one or more other posts to the discussion forum; extracting information from the first resource and the one or more second resources about the discussion forum; and providing the extracted information 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.