The most interesting thing about Okcupid so far is the dynamic of knowing when someone looks at your profile. You would never want that on facebook, but it kind of makes sense for internet dating - it strongly encourages you to make contact instead of just browsing. Of course, you can set it so people won’t see when you look at theirs, but then you can’t see who’s looked at yours, and where’s the fun in that?
When I said it was the most interesting thing, I should have added “until I actually meet someone in real life.“ Presumably that will be more interesting.