"In partnership with the British agency known as Government Communications Headquarters, or GCHQ, the N.S.A. has apparently taken advantage of the vast amounts of data stored in and traveling among global data centers, which run all modern online computing, according to a report Wednesday by The Washington Post. N.S.A. collection activities abroad face fewer legal restrictions and less oversight than its actions in the United States."

Note there's a fair amount of speculation on the specific details of how and what data is collected and shared.