Making the real world more like the online world
One of the most exciting aspects of technology is going to be its ability to improve social networking in the real world, as well as online.
Project PlaceSite is a UC Berkeley project to use technology to bring people together based on geography--in this case, the folks who are logged into the WiFi hotspot of the A'Cuppa Tea cafe.
This is pretty interesting, but I think a killer app would be a Bluetooth version for singles at a bar. Socializing with random folks in a cafe is one thing--finding a better way to pick up chicks (or guys) is on a whole other level of importance.