James Risen and Laura Poitras report:
Since 2010, the National Security Agency has been exploiting its huge collections of data to create sophisticated graphs of some Americans’ social connections that can identify their associates, their locations at certain times, their traveling companions and other personal information, according to newly disclosed documents and interviews with officials.
[…]
The N.S.A. documents show that one of the main tools used for chaining phone numbers and e-mail addresses has the code name Mainway. It is a repository into which vast amounts of data flow daily from the agency’s fiber-optic cables, corporate partners and foreign computer networks that have been hacked.
The documents show that significant amounts of information from the United States go into Mainway. An internal N.S.A. bulletin, for example, noted that in 2011 Mainway was taking in 700 million phone records per day. In August 2011, it began receiving an additional 1.1 billion cellphone records daily from an unnamed American service provider under Section 702 of the 2008 FISA Amendments Act, which allows for the collection of the data of Americans if at least one end of the communication is believed to be foreign.
Read more on The New York Times.