Foursquare is breaking itself to two parts: Foursquare for exploring your location, and whole new app, called Swarm, for keeping up with friends. The idea comes out of the two unique experiences that Foursquare users have always valued: the first, was sharing your location and finding out where your friends are; the second category became finding new places in your area, by reading reviews, viewing menus/pictures, then locating them on a map.
The decision to build Swarm is mainly to simplify and streamline the experience of finding your friends. A post on Foursquare's blog explains it this way:
"We built Swarm because you’ve told us how often you still have to text your friends: “where are you?” and “what you up to later?” We wanted to build a quick way for you to know these two things for all of your friends. With Swarm, you can easily see which of your friends are out nearby, figure out who is up for grabbing a drink later, and share what you’re up to (faster and more easily than you can in Foursquare today)."
In other words, Swarm will be a map of all your friends, and Foursquare will be a map of all your places. The Verge got an exclusive look at Swarm and has more details on how it will work and the company's thinking behind it.