Using your publicly available profiles on Facebook, Foursquare and Twitter, etc, mobile app Sonar, shows you who, how many, and why particular people are relevant to you in a room.

Says founder Brett Martin, “It’s simple- you open up sonar and we tell you that the guy sitting across from you is facebook friends with your college roommate, the dude by the jukebox is a VC that you follow on twitter, and the cute girl by the bar also likes the Arcade Fire and Hemingway.”

This is a particularly difficult problem to solve as you almost never achieve hyper local density, anonymous strangers can be intimidating and most people are hesitant to adopt yet another app!

Sonar solves this problem by using data that people have volunteered and is primarily focused on communicating through public available arenas.

Sonar plans on monetizing as a data play, “Our ambition is to aggregate and analyze all of the real-time geo-demographic data to help brands and SMBs identify, in real time, who and where their audience is, enabling the provision of timely and relevant offers at the point,” says Martin.

Q&A

Judges express concerns about privacy. Paul Carr says he particularly liked Sonar, which is a first.