Whenever Google announces earnings, we have a thread at WebmasterWorld that summarizes how much share Google is taking from the earnings AdSense publishers make.
So if you click on an AdSense ad on my personal blog, how much of that cost-per-click am I get and how much is Google getting.
Based on the earnings report, Google is taking 21% and the remaining 79% is going to me. Now, I doubt this is an exact number, because this includes premium publishers, special partners and so on. So I am sure some of those partners get a higher or maybe even a lower share than the typical AdSense publisher.
But overall, Google is being fair. In fact, Google seems to been paying out publishers more then they have done historically. The thread summarizes:
The past few quarters have been between 75% and 79%.
One other member has a nice post as well:
Revenues up 41%, earnings up 31% - doesn't sound like they're ripping anyone off to me. Now if revenues were up 30% and earnings were up 40%, that would be a different story.
Forum discussion at WebmasterWorld.