I almost didn’t bother to say anything about AdSense WebSearch, but an ebook about AdSense just wouldn’t be complete without at least mentioning it. WebSearch lets you put a search box on your sites. When people search using the box, the search results appear on Google’s server, showing AdSense ads related to the search results above those results.

The earnings per click for WebSearch are horrible. Dismal. Terrible. Do not waste your precious visitors for the beans that Google will pay you in return for doing so. A better paying alternative is to setup your own search script that searches your site, and display regular AdSense ads on the search results page. You’ll get better paying ads that way.

The reason for the other search engine CTRs is highly speculative, but I personally believe it has a lot to do with the sophistication of the searcher. MSN comes as the default page for Internet Explorer on all Windows browsers, and (in my opinion) people who leave their default page to MSN are probably not as savvy net surfers as those who do not.