"This is really a way to make your own version of Google Search that searches over just the content that you care about, or just the content that you're an expert in," says Marissa Mayer, Google's VP of search products and user experience. "You can actually make a smaller version of the Google search engine that just searches URLs and Web sites that you specify."
The Google CSE refines Google Co-Op, a search product launched in May to let users syndicate their knowledge by labeling or categorizing Web sites and making that knowledge available to other Google searchers to improve search result relevancy.
Google CSE is more compelling because it's simpler. Google Co-Op requires some familiarity with XML coding, whereas anyone who has used a menu-driven wizard for software installation should be able to set up CSE in just a few minutes.
Building a CSE offers a chance to profit: Participants in Google's AdSense program--in which publishers share the click revenue from ads supplied to their sites by Google--will make money when searchers click on ads presented alongside their customized search results.