Google recently added the ability for you to report link buyers, which is probably nothing more than a mind control game and a complete waste of time. I recently saw what looked like obvious link buying by Discovery.com. Do you think Google would do anything about it if I reported them? Nope.
Google also recently starting a phased launch of their position placement reports, which is far more beneficial to webmasters, as it shows what sites your AdSense ads are syndicated to. Most sites monetized via AdSense only make a fraction of their full potential, so sharing this data presents more arbitrage opportunities. How you can use this data to profit:
Tags: Cheaply, Google, Links, Quality, Sell, Shows, Willing