MIT has developed a JAVA application for tracking friends by their WiFi network connection and projecting those locations on a campus map. iFind provides user level location awareness. Knowing where your friends are will enable collaborative tools and colleagues to communicate, work, and play together. From the site:

iFIND, a project developed at the MIT SENSEable City Lab, aims to improve social networking through some kind of digitally augmented serendipity. Using iFIND, you and your buddies can instantaneously exchange your locations on campus, talk to users nearby, and microcoordinate more effectively. If you are a geek, you will even be able to arrange meetings in real time using the group’s center of gravity!

Interesting questions concerning personal privacy and user tracking come to mind. It is not entirely clear how much control over this information is left with the user. On the brighter side, can you imagine having this access to cellphone data? You could locate all your family members at a glance. This could also be a valuable tool for tracking people and hard assets in a hospital system or corporate facility. Is the singularity near for collaboration convergence?

The client software is available for download under the GPL. The server software is not available as it ‘does not use any GPL code’. Copies of the client/server protocol documentation are available from MIT by request.

(See: iFind at MIT)
(See also: Trainspotting (1996))