• by Wendy Davis , Staff Writer @wendyndavis, October 24, 2006

Google already captures somewhere around half of all search queries--and that's just among other search engines. Now, Google is poised to start powering far more searches on other publishers' sites.

This morning, the company unveiled its free custom search engine, which allows all Web publishers to harness Google's algorithms. With the customized search feature, publishers can arrange for a query box that only returns results from specified sites.

Publishers other than nonprofits, universities and the government will be required to accept Google ads on their sites and will share revenue with the search company. In other words, the Web sites that use this feature will become part of Google's AdSense network.

Of course, many Web publishers don't necessarily want to join AdSense--despite the possibility of increased ad revenue. Some have arranged to serve pay-per-click ads by Google competitors, while others simply don't want to clutter their pages with text ads.

But it seems fairly certain that a good many publishers will decide that a Google customized search bar on their sites would be a boon--giving visitors a reason to remain on the site while conducting searches, rather than toggling back and forth between the site and a search engine.

Meantime, while AdSense isn't exactly floundering, its revenues are eclipsed by Google-owned sites. The company's last earnings report showed that AdSense revenue came to $1.04 billion--39% of the company's total. With today's announcement from Mountain View, the reach of Google's AdSense network appears bound to increase.