Sonar launched at TechCrunch Disrupt today, to much buzz. It's yet another social networking app that you may briefly use before deleting, after its features have been sucked up by Facebook or Twitter or both or neither.
Sonar is designed to tell you about the connections that exist between yourself and the the other people nearby. It connects with your Facebook, Twitter and Foursquare accounts, and tells you what kind of social media connections you share with other people also using the app nearby. For example, you fire up Sonar, and it tells you that you and some other fella in the room who also fired up Sonar have three shared Twitter friends, and both like Lynard Skynard. Presumably, you can both then strike up a conversation, which perhaps you would have already done had you not been staring at your phone. It will not tell you that you are both sad lonely little men, but you probably already knew that. The app page does note that it is useful for discovering and connecting with "likeminded singles", which I interpret as to mean it can be used for soulless semi-anonymous geoshagging. It is an indictment of modern society, which is now available for free on the Apple App Store.