Location based social service Foursquare has reached its 10 millionth user and has added more features as well as made itself available to Nokia handsets (on Symbian). Foursquare has surpassed 750 million check-ins from users since it's inception in 2009. It is still one of the cleverest ways to claim mayorship of locations people frequent as well avail of specials offered nearby or check out the tips left by other users.
Foursquare has iPhone, Symbian, Android, webOS, Windows Phone 7 and BlackBerry applications.