Gamers play at an IT fair in Germany. The NSA and a British counterpart have deployed agents into several virtual worlds, according to reports, including the online game World of Warcraft. Johannes Eisele/AFP/Getty Images hide caption

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Mohamed Osman Mohamud, then 19, is shown after his arrest on Nov. 26, 2010, in Portland, Ore. Mohamud was convicted of planning to detonate a bomb during a Christmas tree-lighting ceremony, but his sentencing is on hold after revelations that investigators relied to some degree on NSA surveillance. Getty Images hide caption

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Google and five other companies sent a letter last month to members of the Senate Judiciary Committee supporting legislation to reform NSA surveillance programs. Marcio Jose Sanchez/AP hide caption

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Gen. Keith Alexander is director of the National Security Agency, whose duty, his office has said, "requires us to attempt to collect terrorist communications wherever they traverse global infrastructure." Evan Vucci/AP hide caption

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Former chief counterterrorism adviser Richard Clarke is a lead member of a panel appointed by the president to review the country's surveillance policies. Alex Wong/Getty Images hide caption

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