NSA's project, codenamed "MUSCULAR," works in conjunction with its British counterparts at GCHQ, to intercept the cables between Google's and Yahoo!'s data centers around the world.
In a "top secret" document dated January 9, 2013, the spy agency's acquisitions unit sends millions of records daily from Yahoo and Google data centers back to its headquarters in Fort Meade. In the preceding 30 days, the agency collected 181 million new records alone, including metadata - such as traffic records and details relating to customer data - as well as the contents of communications.
The program works by exploiting a weakness between Google and Yahoo's cloud systems.
The news was first reported by The Washington Post, citing documents received from Edward Snowden and interviews with knowledgeable officials.
