Since its inception, the SenseCam has been used as a lifelogging device with support for memory recall being the primary intended application. However, as with the development of all good technologies, we tend to find new applications that we didn't think of in the first place and these unintended applications can sometimes outgrow the original ones. In the case of the SenseCam, we have been using the image and sensor data gathered in order to determine the activity profiles and characteristics of individuals and to compare them against the peers as well as to track changes in activities over time. We have also been using SenseCam data to help compute the wearer's individual carbon footprint by detecting driving and other transport mechanisms. When our use of SenseCam is coupled with a simple domestic electricity meter and the combined data forms part of the sensor web, then the calculation of carbon footprint information, and determining the activity profiles of individuals or groups, becomes even more accurate. The net result is that by using two simple sensor devices, the SenseCam and a domestic energy meter, we can characterise much of the activities and carbon footprints of individuals, a classic case of good technology (SenseCam) finding new and unforeseen applications.