I think this is pretty useful for broadening your social graph, or as normals call it - making new friends. There seems to be a trend towards using technology to facilitate having experiences with people that aren't your closest friends but that you have some kind of connection to or common interest with (see grubwith.us). Maybe it's a new kind of social dating, although it certainly could be used for making/solidifying platonic relationships. This is obviously useful for someone that moves to a new city or just wants to explore new relationships. Also, it allows you to throw an idea out there to see if there's interest before having to figure out all the scheduling details.