NPR story: Go Green for students

NPR story about students given cellphones to track the carbon footprint of their commute. The students like it because they can do something about climate change. On the other hand, some comments from viewers on the web expressed concern about the sustainability of cellphone - the product. My take is it is not enough reason to not do mobile apps that promote sustainability. We all use cellphone as a necessary part of modern life so why not make it do something useful for the environment too?