The National Security Agency has been mining its massive collections of email and phone data for several years to create extensive graphs of some Americans' social connections, including their associates, travel companions and locations, according to The New York Times.
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 Snowden and interviews with officials.
The graphing, or contact chaining, is conducted using metadata details about phone calls and emails 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, but that category is extremely broad and may include anything from data about terrorism and drug smuggling to foreign diplomats and economic talks.