An interesting note about the dating market is that there is almost no consistent repeat business. People don't get fed up with the site and leave - they either get a match, or they don't. If anything, people might return after a few months because they found a moderately successful relationship. To my mind, that's precisely the reason something like this can work. If Facebook had a lousy interface, people would eventually lose interest because they wouldn't stay continually interested. But for PoF, that's just not a factor. They come for the results, and if it works, the interface is irrelevant. They'll be back regardless, and if they aren't, there's always more people looking for a date.