The term "bug" is too confusing. I thought for a while when reading your page that I point this service at my website and it somehow searches for errors in the programming. I only kept reading because I wanted to figure out what neat trick you had for that.

I get the spy novel reference now, but I think it's just too abstract and too close to a conflicting term to be of use. Especially when there are terms for that (spyware, cookies) that everyone knows already. Don't reinvent the wheel.