I find OKCupid to be a very interesting business. The guys who run it are also definitely hackers; they've written about the science behind their matching algorithms, their in-house web framework (which is Open Source, though I'd never touch the stuff, as it is a C++ web app framework, which is just weird and masochistic), and quite a bit about their user data (as in this post). It's very often interesting. At least one of them used to comment here at HN occasionally, but I don't recall his nick so I don't know if he's still a regular. Nonetheless, as a community, I think this is definitely relevant to our interests.