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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A promotional image from Renew shows one of its recycling/advertising kiosks in London. City officials asked the company to stop recording data about the phones of passing pedestrians. Renew hide caption

itoggle caption Renew

Value and meaning come from relationships and context. A physical object, such as a quarter, only holds the value we give it. It has no intrinsic worth. 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

itoggle caption Justin Sullivan/Getty Images

Big Data may not be much to look at, but it can be powerful stuff. For instance, this is what the new National Security Agency (NSA) data center in Bluffdale, Utah, looks like. George Frey/Getty Images hide caption

itoggle caption George Frey/Getty Images