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AdSense for content publishers, who make up the vast majority of AdSense publishers, earn a 68% revenue share worldwide. This means Google pay 68% of the revenue that they collect from advertisers for AdSense for content ads that appear on your sites. The remaining portion that they 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 Google incur in building products and features that enable AdWords advertisers to serve ads on AdSense partner sites. Since launching AdSense for content in 2003, this revenue share has never changed.
Google pay AdSense for search partners a 51% revenue share, worldwide, for the search ads that appear through their implementations. As with AdSense for content, the proportion of revenue that Google keep reflects their costs, including the significant expense, research and development involved in building and enhancing our core search and AdWords technologies. The AdSense for search revenue share has remained the same since 2005, when they increased it.