Only charge developers a monthly fee? Last I checked it is hard to find developers and not hard for developers to find work. I doubt many developers would pay to be listed, I know I wouldn't.
Sure there are many developers who won't need the service, but there also plenty of developers who wouldn't mind having a service to filter out the silly and bogus request. It's not about finding any kind of work, it's about finding the right work at the right pay. The goal is to match quality jobs with talented developers.
