John Battelle's Searchblog: AmazonSense? -- This would have 3, or potentially 4 vendors, in the "get paid for ads on your site" space. Google, Yahoo, potentially Amazon and MSN. The more the better for publishers, although advertisers are going to have to manage even more content networks of distribution, which ought to be good news for the folks who build the tools to manage ad campaigns. And, perhaps, not as good for the small company trying to figure out where to advertise online. I wonder if that will solidify Google's hold due to the confusion factor.