Many tweens and teens love FourSquare, a free application available for GPS-enabled smartphones.

Here are 4 vital things you need to know about FourSquare to keep your kids safe when they're using the location-based social networking app.

1. It's not just a game:

On FourSquare, your child earns points for “checking in” at certain locations and earns badges (checkins at 20 different pizza places, for example.) If she frequently checks in at the same place, she could become “mayor” of that location.

But even though it sort of feels like a game, FourSquare is actually a social network where people can