I don’t use Foursquare because I don’t like the idea of announcing to the whole world where I am at the moment. I know I will never be comfortable with announcing all my every move and destination to strangers. I understand why some people use it but definitely not me.
Recently, the Foursquare team put back the check-ins from nearby friends feature to the app. You see, it was previously removed but a lot of Foursquare users complained. The feature is back, at least, for iPhone and BlackBerry users with the recent app updates. The Android version has yet to be released though.