If you have a blog, there’s a good chance you’ve got a Google AdSense block somewhere on your site. AdSense has long been a way to help monetize your site with contextual ads. But it’s always been vague as to how your income is determined.

This morning, Google revealed exactly how much they take as their share from AdSense sales “in the spirit of greater transparency.” According to the release placed on their blog, they take:

• 32% of content ads (the publisher gets the remaining 68%)
• 49% of search ads (the publisher gets the remaining 51%)

The content ads are those placed alongside web content, while AdSense for search allows publishers to place a custom Google search engine on their site and obtain revenue from ads shown in the results.

And what does Google do with their cut? They use the money for “continued investment in AdSense — including the development of new technologies, products and features that help maximize the earnings you generate from these ads.”

Do you think this is a fair share? Do you use any other contextual ad services?

Nikki Katz is the Managing Editor for the BlogWorld Blog. Feel free to follow her Twitter @nikki_blogworld and @katzni