The Foursquare Swarm app will launch next month as a new offering from Foursquare, designed to give a different, more social experience that doesn't revolve around check-ins, although users can still check in via Swarm. Rather than updating or replacing Foursquare, Swarm will be offered in addition to Foursquare.
Swarm is an alternative for people who don't want to be prompted to check in immediately upon opening the app, or have their exact location pinpointed and shared. Instead, Swarm is capable of giving a more general idea of the neighborhood the friends in your network are. In addition to being safer, it's easier to see who's in the nearby area and makes the app more about locating nearby people rather than simply announcing your own location.