Socially Mobile
Social Networking applications team up with Mobile phones to deliver this hot new service,

What does the service provide?

Say you’re young and single, and you’re out on the town one Saturday night. You take out your mobile phone and tap in the name of the restaurant where you're hanging out. You get a list of friends, and friends of friends, within 10 blocks. You can message each other about getting together, and maybe send a photo of yourself.

MITs Technology Review has done a good article on it

Now this is a new reason why i cant do away with my mobile phone though it is such a pain at time.