I went to a Cambridge Usability Event on Monday night: Nick Lansley made an interesting presentation about enabling partially sighted people to use Tesco.com more effectively.
In the chatting afterwards, I was struck by the similarity between Google Adwords (and paying for your position on your ad specifically) to product placements in grocery stores, whereby the washing powder manufacturer pays a premium to the retailer to place his product at chest height, rather than at ankle level (where the own brands are).
So it ain't all that new. As Sherlock Holmes said, "Everything comes in circles - even Professor Moriarty. . . It's all been done before, and will be again."