I've worked in this space, and sadly I suspect most people would struggle with it. Any newly-launched dating/hookup site suffers from the same problem: lack of users.

You promote it, you seed it with your friends, and then the obvious thing happens:

* Users find your site.

* Users sign-up, rarely.

* Users searches the site for people in their vicinity. Finds zero results.

* User logs out and never returns.

I tried to solve this problem by launching in a craigslist-esque fashion, launching on a city-by-city basis. But sadly there is a lot of scummy affiliate marketing in this area, and advertising is just a way of losing money quickly.

Most of the big sites are paid, and the free sites struggle unless very niche/location-centric..