From Chris Beasley’s post:
Amazon is apparently looking into the feasibility of starting their own ad network like Adsense. They’ve been contacting select members of their associates programs, including myself, asking if we’d like to be beta testers. The way they want the beta test to work is to give you a special code for Amazon’s Keywords Recommends banners (the banners that you feed a keyword to and they show related products) and have this special code then show these new ads 50% of the time.
When I first heard about this I thought it’d be Amazon product listings displayed in an Adsense-like way and I figured it’d analyze your content for for products to serve, but they’d be Amazon products. Turns out I was wrong, they want their own contextual advertising network.