Cell Phones as Trackers

ProPublica’s Peter Maass and Megha Rajagopalan explain how the cell phone, the device that most people carry around all the time, can be used as a tracker. In a piece jointly published by ProPublica and the New York Times Sunday Review, they describe how cell phones track "what we buy, where and when we buy it, how much money we have in the bank, whom we text and email, what Web sites we visit, how and where we travel, what time we go to sleep and wake up.”  They also look into how much of that data is shared with companies who use it for marketing.