Cloak is a new smartphone app that helps you avoid nearby friends/frienemies/enemies by constantly monitoring their Foursquare, Instagram and other geo-tagged locations and alerting you to their position. Alternatively, go home and lock the door.
Here's how the app works. After downloading Cloak for the first time, you can connect it with Foursquare and Instagram (with more networks to come soon). Cloak then plots where your Foursquare and Instagram contacts are, according to their most recent check-ins. You can casually check the map, or -- for exes, chatty neighbors and other undesirables -- "flag" them to receive an alert when they pass within a preset radius.
I mean, sure, provided all the people you want to avoid are constantly updating their Foursquare and Instagram. But are those the people you're really worried about anyways? Because I'm more concerned with the people who operate rogue and can pop up anywhere. Look behind you. See me waving? "Is that a knife?" PREPARE TO DIE.
Thanks to Charlie H and Lena, who avoid people they don't want to see the old fashioned way: hiring hitmen.