Developer Scott Garner developed the 'Hell is Other People' app in order to help you stay away from people that you know. The app analyzes FourSquare check-in data in order to see where people are congregating around the city. The app then plots out safe friend-free areas so that you can go about your business in peace.
Hell is Other People starts by plotting out all check-ins from FourSquare users that you know. Upon finding everyone's location, the app calculates "optimally distanced safe zones" and marks them with green dots. Each safe point can be clicked in order to reveal the latitude, longitude, address and Google Street View picture.
Garner developed the app not as a serious tool, but as satire and social commentary.