The social graphing began in 2010 after the NSA lifted restrictions on the practice, according to an internal January 2011 memorandum, the Times reported online Saturday. It based its article on documents obtained by former NSA contractor Edward J. Snowden and interviews with officials.
The graphing, or contact chaining, is conducted using details about phone calls and e-mails, known as “metadata,” but does not involve the communications’ content, according to the documents cited by the Times. It is supposed to be done for foreign intelligence purposes only, the documents state, but that category is extremely broad and may include everything from data about terrorism and drug smuggling to foreign diplomats and economic talks.
The revelation is the latest in a string of disclosures that began in June, when The Washington Post and the British newspaper the Guardian broke stories, based on Snowden’s documents about the NSA’s PRISM program, which collects digital communications from U.S. Internet companies, and about the collection of call-detail records from U.S. phone companies.