Amazon.com has announced ClickRiver, a PPC service letting advertisers buy text link ads on their search result pages. While ClickRiver will make money just like Google AdWords does, Amazon sells products, unlike Google, which means the ads will be competing with their own sales, and earning far less perclick than Amazon earns on sales. Still, Amazon already runs sponsored links, and the idea of competing with yourself seems silly.
Maybe a smarter idea would involve something more along the lines of Snap.com’s cost-per-action ads, where advertisers only pay when they get a sale. In that case, instead of Amazon making money from the ads, it would come from the sales of their advertisers, just like a commission, and could be competitive with the money Amazon would have made if it had completed the sale itself.