Useful social-networking tool, or way for geeks to

Trepia: your instant community provide an IM client that instead of your buddy list, shows people “near” you - on the same WiFi network, although I don’t know how it works for non-WiFi users.

I’m not convinced that it’s particularly useful, I mean, it’ll let you message people who are nearby… hmm… can’t I just walk up to them? Okay, I probably wouldn’t, but does that just make it a tool for shy geeks to talk to other shy geeks?