Google has finally disclosed the percentage of revenue it keeps from publishers running its Adsense system which places ads alongside content on sites like this one.
AdSense for content publishers, who make up the vast majority of our AdSense publishers, earn a 68% revenue share worldwide. This means we pay 68% of the revenue that we collect from advertisers for AdSense for content ads that appear on your sites. The remaining portion that we keep reflects Google’s costs for our continued investment in AdSense — including the development of new technologies, products and features that help maximize the earnings you generate from these ads. It also reflects the costs we incur in building products and features that enable our AdWords advertisers to serve ads on our AdSense partner sites. Since launching AdSense for content in 2003, this revenue share has never changed.