In the Mobile 2.0 project, Nicolas Belloni has developed a service that helps you locate friends when you are travelling on the same subway line to work. To work on as many phones as possible, the Subway Friend Finder uses self-reported location and a simple web interface to indicate if you are in the same car as anyone you know. The Friend Finder will be presented as a Work-in-Progress poster at CHI 2009 in Boston, the annual ACM SIGCHI conference on Computer-Human Interaction.

On the video link you can see Nicolas Belloni give a short demonstration of the service!