Amazon's adoption of ad-supported ebooks is shifting from possible to likely. From @radar
It all started harmlessly enough with Amazon's Kindle with Special Offers. That's the cheaper Kindle that displays ads when the device is in sleep mode or at the bottom of the screen when paging through the owner's catalog of books. It is very unobtrusive and, since it lowered the price of the device, has made that Kindle an extremely popular device.
Given that Amazon's goal is to offer customers the lowest prices on everything, what's the next logical step? How about even lower prices on ebooks where Amazon starts making money on in-book ads? Think Google AdWords, built right into the book. Of course, Amazon won't want to use Google's platform. They'll use their own so they keep 100% of the revenue.