1. A system for managing advertisement placement over a network, comprising: a processor; and a tangible storage medium storing thereon program logic for execution by the processor, the program logic comprising: logic executed by the processor to retrieve, over a network, a plurality of content items from a plurality of content sources; logic executed by the processor to identify a plurality of advertisements embedded in the plurality of content items; logic executed by the processor to identify keywords of the plurality of advertisements; logic executed by the processor to determine similarity rankings of the plurality of advertisements based at least in part on the keywords; logic executed by the processor to select a keyword based at least in part on the similarity rankings, where a historical price from a keyword seller for the keyword is less, by a defined amount, than a historical price from a click buyer; and logic executed by the processor to purchase the keyword from the keyword seller for placement of a first linked advertisement, the first linked advertisement configured to be selected to cause the presentation of a second advertisement of the click buyer.
1. A system for managing advertisement placement over a network, comprising: a processor; and a tangible storage medium storing thereon program logic for execution by the processor, the program logic comprising: logic executed by the processor to retrieve, over a network, a plurality of content items from a plurality of content sources; logic executed by the processor to identify a plurality of advertisements embedded in the plurality of content items; logic executed by the processor to identify keywords of the plurality of advertisements; logic executed by the processor to determine similarity rankings of the plurality of advertisements based at least in part on the keywords; logic executed by the processor to select a keyword based at least in part on the similarity rankings, where a historical price from a keyword seller for the keyword is less, by a defined amount, than a historical price from a click buyer; and logic executed by the processor to purchase the keyword from the keyword seller for placement of a first linked advertisement, the first linked advertisement configured to be selected to cause the presentation of a second advertisement of the click buyer. 3. The system of claim 1 , wherein the program logic further comprises logic executed by the processor to provide linked advertisements to the keyword seller.