Welcome to WebmasterWorld Guest from 220.127.116.11
With the caveat that three days data is probably indicative of nothing significant, about 8% of my site visitors use the custom search engine and about 8% of them click an ad. I'm sure many of my site's visitors haven't quite figured out what it is yet.
I know my site doesn't cover the total breadth of its subject matter. Let's just say no site ever will, it's a pretty large subject. My custom search engine is set up so my site's visitors can find information from other sites on this subject. I'm liking it for my own research. It's a service for my site visitors first, and if puts a few dollars in my pocket in the process, that's cool beans.