6. A computer system of an electronic marketplace for providing an item relating to web page content, comprising: storage for a plurality of previously-submitted queries that have been submitted by users of the electronic marketplace, and indications of popularity of the queries among said users; at least one processor operable to cause the computer system to at least: responsive to a link-selection request by a user for a web page of a media web site provided by a media content server, receive an automatically generated request from the media content server to provide information about the item based at least in part on the web page content displayed on the media web site, the media content server being different than the computer system of the electronic marketplace, the web page content submitted in the generated request being derived by the media content server; match at least a portion of the web page content to the item by at least: identifying, from the storage, the previously-submitted queries that correspond to at least a portion of the web page content; selecting an identified previously-submitted query as a matching query based at least in part on a relevance of the matching query to the web page content and a popularity of the matching query; and identifying the item among a set of items that corresponds to the matching query; and provide, asynchronously relative to when the web page content is made available by the media content server, the information about the identified item for display on the media web site along with the web page content.
6. A computer system of an electronic marketplace for providing an item relating to web page content, comprising: storage for a plurality of previously-submitted queries that have been submitted by users of the electronic marketplace, and indications of popularity of the queries among said users; at least one processor operable to cause the computer system to at least: responsive to a link-selection request by a user for a web page of a media web site provided by a media content server, receive an automatically generated request from the media content server to provide information about the item based at least in part on the web page content displayed on the media web site, the media content server being different than the computer system of the electronic marketplace, the web page content submitted in the generated request being derived by the media content server; match at least a portion of the web page content to the item by at least: identifying, from the storage, the previously-submitted queries that correspond to at least a portion of the web page content; selecting an identified previously-submitted query as a matching query based at least in part on a relevance of the matching query to the web page content and a popularity of the matching query; and identifying the item among a set of items that corresponds to the matching query; and provide, asynchronously relative to when the web page content is made available by the media content server, the information about the identified item for display on the media web site along with the web page content. 10. The computer system of claim 6 , wherein the popularity of a particular previously-submitted query is based at least in part on user requests for information about a product identified in results of a query engine having processed the particular previously-submitted query.