I think having a bit of an explanation of what the site is and how it works would be very helpful. Having a video of you using the website to show some features while also explaining how the site can help people will go a long way. Other than that I would recommend starting small and getting everyone you know to talk about it. Perhaps you should also try to market it on a local college campus if there is one near. College kids are always looking for ways to meet people who are interested in them (read: get laid) and I'm sure would be glad to check your stuff out. Or perhaps you could try and get in touch with the guys from like a little and see if you could do something with them.