The August issue of Wired magazine features an article by Clive Thompson on how feedback loops get people to change their habits. As a Prius driver, I can attest to the fact that the consumption feedback monitor screen has changed our driving habits as we try to constantly increase our fuel efficiency.
"There's already solid evidence that feedback mechanisms can change eco-behavior. ...Imagine if your daily consumption were part of your Facebook page -- and broadcast to your friends by RSS feed. That would trigger what [Ambient Orb creator] Ambient Devices CEO David Rose calls the sentinel effect: You'd work harder to conserve so you don't look like a jackass in front of your peers. This isn't as far-fetched as it sounds. The design firm DIY Kyoto (as in Kyoto Protocol) recently began selling a device called the Wattson , which not only shows your energy usage but can also transmit data to a Web site, letting you compare yourself with other Wattson users worldwide."
Awesome; the power of feedback combined with the power of social networking.