What makes a dating site work is having people who are going to chime with each other; you don't need mass-market hegemony. So, what you want is demographic sim

What makes a dating site work is having people who are going to chime with each other; you don't need mass-market hegemony. So, what you want is demographic similarity but little social intermixing – people drawn from similar, geographically close but socially-separate communities. In other words you need a niche. I'd hit up – maybe even sponsor – something like book groups. (Pick a major metro and blanket it; that buys you the geographic proximity). Then, once you're rolling, use the success to knock over the surrounding geographies.