1. A computer-implemented method comprising: a) accepting, with a computer system including at least one computer on a network, a search query; b) searching, with the computer system, using information from the search query, a searchable data structure including advertiser Web page information to generate advertisement search results; c) accepting, with the computer system, the advertisement search results; and d) retrieving, with the computer system, automatically, independent of end user acts, and responsive to the search query, at least one advertisement using at least a portion of the accepted advertisement search results, wherein the at least one advertisement is retrieved from a set of advertiser information, the set of advertiser information including information identifying advertiser Web pages, and wherein the searchable data structure includes advertiser Web page information that is generated from information automatically extracted exclusively from the identified advertiser Web pages without the need for expressly entered advertiser entered targeting information.