There are various premade dating site systems that can be found by googling (mostly non-free). Similarly, a search for "ruby on rails dating site" turns up an o

There are various premade dating site systems that can be found by googling (mostly non-free). Similarly, a search for "ruby on rails dating site" turns up an open source social network, http://lovdbyless.com/ http://lovdbyless.com/ , which might be a good place to start. However, the important question isn't how to get the code for the site working, it's how to get a community established. No one wants to be one of the first people using a dating site, because then they can't find anyone else on it. The value of a dating site increases with the size of the community, because that makes it more likely that a user will find someone who is compatible with them. The market is pretty saturated right now, and it would be hard to compete with the larger players unless you have a very compelling secret sauce (which it doesn't sound like you do). There's probably still room for very niche sites, but if you're not a member of a niche it might be hard to get adoption. If you don't have a compelling answer for how you're going to get users - and nothing with the words "viral marketing" in it counts - stop until you do.