" The NSA’s original mission was to collect foreign intelligence. But it appears to have drifted away from its original goal, like a vast supertanker floating away from its anchor. It is now sucking in a lot of domestic communications. In this new era of Big Data, the agency moved from the specific to the general; from foreign targeting to what Snowden called ‘omniscient, automatic, mass surveillance’. The "

― Luke Harding , The Snowden Files: The Inside Story of the World's Most Wanted Man