15. Apparatus for determining at least one supplemental advertisement to be presented on an advertiser landing Web page, the advertiser landing page being referenced from a user selected advertisement, comprising: a) one or more processors; b) at least one input device; and c) one or more storage devices storing processor-executable instructions which, when executed by one or more processors, perform a method of: i) accepting advertiser policies provided by an advertiser associated with the advertiser landing Web page, the advertiser policies including 1) a condition that supplemental advertisements on the advertiser landing page must not include any links to another document, and 2) a condition that supplemental advertisements on the advertiser landing page advertise a different product or service than the product or service advertised in the user selected advertisement; ii) accepting search query information sourced from a user device; iii) generating, for presentation on the user device, a document with search results determined using the search query information and at least one advertisement determined using the search query information, wherein each of the at least one advertisement includes a reference to an advertiser landing Web page and wherein each of the at least one advertisement advertises a product or service; iv) transmitting, to induce presentation on the user device, the generated document including the search results and the at least one advertisement; v) accepting a selection, sourced from the user device, of one of the at least one advertisement; vi) determining at least one supplemental advertisement using 1) the search query information, each of the at least one supplemental advertisement advertising a different product or service than the and 2) the accepted advertiser policies including the condition that the at least one supplemental advertisement must not include any links to another document, and the condition that the at least one supplemental advertisement advertises a different product or service than the product or service advertised in the selected at least one advertisement; and vii) generating, for presentation on the user device, the advertiser landing Web page referenced from the selected at least one advertisement, the advertiser landing Web page including the at least one supplemental advertisement determined.
15. Apparatus for determining at least one supplemental advertisement to be presented on an advertiser landing Web page, the advertiser landing page being referenced from a user selected advertisement, comprising: a) one or more processors; b) at least one input device; and c) one or more storage devices storing processor-executable instructions which, when executed by one or more processors, perform a method of: i) accepting advertiser policies provided by an advertiser associated with the advertiser landing Web page, the advertiser policies including 1) a condition that supplemental advertisements on the advertiser landing page must not include any links to another document, and 2) a condition that supplemental advertisements on the advertiser landing page advertise a different product or service than the product or service advertised in the user selected advertisement; ii) accepting search query information sourced from a user device; iii) generating, for presentation on the user device, a document with search results determined using the search query information and at least one advertisement determined using the search query information, wherein each of the at least one advertisement includes a reference to an advertiser landing Web page and wherein each of the at least one advertisement advertises a product or service; iv) transmitting, to induce presentation on the user device, the generated document including the search results and the at least one advertisement; v) accepting a selection, sourced from the user device, of one of the at least one advertisement; vi) determining at least one supplemental advertisement using 1) the search query information, each of the at least one supplemental advertisement advertising a different product or service than the and 2) the accepted advertiser policies including the condition that the at least one supplemental advertisement must not include any links to another document, and the condition that the at least one supplemental advertisement advertises a different product or service than the product or service advertised in the selected at least one advertisement; and vii) generating, for presentation on the user device, the advertiser landing Web page referenced from the selected at least one advertisement, the advertiser landing Web page including the at least one supplemental advertisement determined. 21. The apparatus of claim 15 wherein the processor-executable instructions which, when executed by one or more processors, further perform: accepting an election by the advertiser associated with the advertiser landing Web page to allow the at least one supplemental advertisement to be rendered with the advertiser landing Web page; transmitting to induce presentation on the user device, the advertiser landing Web page referenced from the selected at least one advertisement and the at least one supplemental advertisement determined by the computer system; providing compensation to the advertiser associated with the advertiser landing page for allowing the at least one supplemental advertisement to be rendered with the advertiser landing Web page.