Want to avoid bumping into your ex, frenimy, or an annoying co-worker? Cloak might be the solution to your problem. It is a free iPhone app that grabs location check-ins from your contacts' Foursquare and Instagram accounts, and organizes them into a user-friendly map.

Just click on a bubble on the map, and you'll see details like the person's name, their location, the time they checked in, and more. A faded image means the person checked-in a while ago. You can also opt to receive notifications when someone enters a preset radius.

Brian Moore, the creator of the app, got the idea when he awkwardly bumped into his ex-girlfriend four separate times in six months. He started working on the app along with other collaborators including co-founder Chris Baker. It took them 7-8 months to develop the application.

According to Moore, people have already started using the app in creative ways. Some have started setting up notifications for people they do want to see. As of now, the app scrapes only Foursquare and Instagram, but developers say that they'll be adding more social networks and features in the future.

"Social has had its moment in the sun. Now people are beginning to revolt," Baker says. A similar anti-social experiment, "Hell is other people", was launched last year. The website tracks your Foursquare friends, and calculates optimally distanced locations for avoiding them.