Publishers complain about different policies and practices, but at the end of the day, Google controls the ad server and the other major points in the pipeline.
They control so much demand through AdX and AdWords that they have all the leverage.
This arrangement has made it possible for Google to extract 30% of publisher revenue through various fees - and in some cases even more.
The ad server layer is where Google implemented many of its most anticompetitive policies, including last look.
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