Via Digg, I read this article about Nokia harvesting data from Berkeley students and GPS-enabled phones:

Each student car was issued a Nokia N95 phone with GPS and special traffic-monitoring software developed by Nokia’s Palo Alto, Calif.-based research lab–plus a Bluetooth headset. As the students drove the freeway, the phone sent data about each car’s speed and position back to the company’s research facility. The data is compiled and used to predict traffic patterns and help drivers get where they need to be quickly.

I really like the idea of using a sample of people as a sort of indicator of the environment. Sort of like those little balls in Twister!