Usability 
A new geolocation enabled mobile mashup from Dmitry Namiot that creates a user forums for discussing local points of interest. City Forums uses you phone's location to get a list of places from Foursquare. Tapping a place name opens a Discus forum where you can read and leave comments on the place. Works with mobile browsers with geolocation support (iPhone, Android, Samsung bada, Opera Mobile 10.1, etc.)