A realty sign hangs in front of a home for sale in Orlando, Fla. Housing advocates say banks, stung by the housing crisis and its fallout, remain reluctant to lend. John Raoux/AP hide caption

itoggle caption John Raoux/AP

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