When you learn how to force people to check-in to a club and broadcast it, you'll have this app. Until then, it's really difficult.

I once had an idea was that you would open up the app and it would have two buttons: (1) MALE (2) FEMALE. Clicking one would check you into that club. This would solve what a lot of people want -- where are the people & who are those people?

Even something that simple though -- what's the reward for the user checking in? On Foursquare, it was awards and badges and stuff. If you could do that around night-life, you might have something.