Dopplr's kind of cool, but I'm still looking for the right thing: I travel occasionally, and in reality, it's not my circle of friends that needs to be informed, it's the people that I could potentially meet somewhere. For instance, I'm part of Debian (although I really ought to officially retire) and the Apache Software Foundation. There are lists where I can mention that I'm going to be somewhere, and more often th…
Hi David -- There are a few sites like that. You could try travbuddy.com if you are interested in meeting travelers by location or showing them around your hometown, although it has less of a tech slant. couchsurfing.org has more of a backpacking focus, but they also have regular meet-ups around the world.