i don't quite understand what it will tell me though, people arent buying my site necessarily its not a book i suppose, and wont the decision to click on a specific name depend more on what they were looking for than what the name actually is?

It will tell you which site name gets more clickthroughs, which is a proxy for interest. Keep everything in both ads the same, except the name.

The name that makes people click, out of curiosity or whatever motive, will likely be the better name. If you ever do advertise your site, you will have one factor in your favor already. It is ok if you don't have a "product," just put a "site coming soon" message up.