Mobile computing has, in the past half a decade, taken off in ways that were not anticipated. An important component of this revolution has been the co-evolution of cloud computing, which has been used to enhance the capabilities of a mobile device. If this revolution is to be sustained, it is imperative that we leverage the strengths of mobile devices, namely the presence of many useful sensors, in novel ways that greatly increase their utility. Sensor data (audio, images, video) sharing has proven to have enormous social value, and a challenge in sensor data sharing but one that provides interesting opportunities, is to ensure the privacy of sensor data. In this talk, I will present two pieces of recent work that suggest a common framework within which to explore privacy issues for sensor data.