Your Ad Here. And Here. And Here

How a web of middlemen is hijacking the placement of online ads -- and cashing in: " The gravy train starts with big advertisers. The companies they hire, such as Yahoo! (YHOO ) and Google Inc. (GOOG ), tally the clicks the ads generate and charge accordingly. But to juice the returns, those outfits sign up partners who distribute the ads in return for a fee, and those partners sign up other partners. With each layer vying for more locations to showcase lucrative ads, there's an incentive for someone along the line to deliver them via surreptitiously installed programs."