Find Friends Nearby shows users which of their friends — and strangers who have shared interests — are close to them in real time.
Unlike Foursquare, which makes users physically check-in before it reveals their location to friends, Facebook isn’t looking for your approval.
Both people must have the Find Friends Nearby feature turned on before Facebook makes their locations public. But of course, Facebook has turned this feature on by default, so you have to find it buried in the app to turn it off. Or you can turn off your location on your phone altogether.
The app doesn’t say specifically where the nearby Facebook user is though, right now it just allows you to add that person as a friend.
To find the feature on your Facebook mobile app, go to Menu > Apps > Friends Nearby > Other Tools > Find Friends Nearby.