Since almost every comment is missing the nature of the change and its effects, let me put it in a clearer way: Google stated that they were holding naive seco

Since almost every comment is missing the nature of the change and its effects, let me put it in a clearer way: Google stated that they were holding naive second price (with an asterisk) auctions and moved on to holding more optimal auctions. Optimal auctions are the ones where you set reserve prices and assign handicaps to each individual buyer to make the auction more competitive and yield higher revenue, like Google has done. (How to calculate optimal reserve prices and handicaps is left to reader, should be fairly trivial because economics is not a real science.) So, in effect Google has increased advertising prices without communicating the fact, in a way that the participants could also attribute the cost increase to changing marketing landscape. The fact that Google expected 15% more revenue puts them over the standard 5% test for significant market power, and hiding the price hike is easy evidence for the abuse of such power.