I've been doing a lot of background research on personal sensing applications and devices. Usually, they involve hooking up some kind of sensor to a network-enabled device (often a mobile phone) and uploading data to a shared repository. Sometimes the sensor is embedded in the phone (like a noise sensor); sometimes the sensor is an external device that has to be manually hooked up (usually through an intervening device like an Arduino). This model is a little different.
E. Agapie, G. Chen, D. Houston, E. Howard, J. Kim, M. Y. Mun, A. Mondschein, S. Reddy, R. Rosario, J. Ryder, A. Steiner, J. Burke, E. Estrin, M. Hansen, M. Rahimi, “Seeing Our Signals: Combining location traces and web-based models for personal discovery” In Proceedings of the 9th IEEE Workshop on Mobile Computing Systems and Applications (HotMobile 2008), Napa Valley, CA, February 25-26, 2008.
It proposes combining GPS traces of human movement with available online data. The user does not carry any sensors (except GPS). Instead, the point is to "index our life into other available datasets about the world around us."
What I also find interesting about this paper is its demonstration of a new set of beliefs about environmentalism: that areas of "interaction between individuals and
the environment" include "transportation mode choice, overall carbon footprint, and opportunities for healthy eating." As recently as three years ago, eating probably wouldn't have been included on that list.