Cell towers are constantly tracking the location of mobile phones. And that data, federal courts have ruled, is not constitutionally protected. Steve Greer/iStockphoto.com hide caption

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Google, like Facebook, Microsoft and other Internet companies, is concerned that data requests from U.S. surveillance agencies could ultimately damage its reputation in the U.S. and overseas. Justin Sullivan/Getty Images hide caption

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Shwetak Patel (foreground), a MacArthur Fellow, recognized that every device in a home has a unique signature that can be used to track energy usage. The data collected by Patel's system showed that digital video recorders were responsible for 11 percent of this home's power use, just one example of The Human Face of Big Data. © Peter Menzel 2012/from The Human Face of Big Data hide caption

itoggle caption © Peter Menzel 2012/from The Human Face of Big Data

Mobile apps and devices track a user's health statistics. But those data are sometimes sold and can end up in the hands of employers and insurance companies. iStockphoto.com hide caption

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Researchers are increasingly using cloud computing to discover new drugs and medical treatments. Cloud computing is often cheaper and quicker than in-house computing. iStockphoto.com hide caption

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