The US National Security Agency (NSA) analyzes data from phone calls, emails, location services, internet profiles, bank records, flight manifests, and more to construct detailed social graphs of people, including Americans, according to a new report from the New York Times.

It’s helpful to start with an NSA slide, published by the Times, that explains some of the process used to construct relationships among people and organizations:

​

Since November 2010, the NSA has been conducting “large-scale graph analysis on very large sets of communications metadata without having to check foreignness,” documents provided by Edward Snowden, the former NSA contractor, reveal. Metadata refer to the time, location, participants, and other information about phone calls and emails that the government ingests from telecommunications companies under court orders.

The system for collecting and analyzing that data is called Mainway. It was first revealed by USA Today in 2006. Mainway handles staggering amounts of information, according to the new Times report (emphasis added):

An internal NSA 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…. The overall volume of metadata collected by the NSA is reflected in the agency’s secret 2013 budget request to Congress. The budget document, disclosed by Mr. Snowden, shows that the agency is pouring money and manpower into creating a metadata repository capable of taking in 20 billion “record events” daily and making them available to NSA analysts within 60 minutes.

The analysis of phone and email records is augmented by “enrichment” data from other sources, which the Times said includes Facebook, GPS provider TomTom, voter registration rolls, property records, tax information, bank codes, and so on. The result is a social graph of people that can include up to 164 “relationship types,” some of which are mentioned in the slide above: groupMember, listedIn, addressedBy, ofInterestTo, etc.

Everyone who uses cell phones, the internet, banking systems, and other technology leaves behind a vast trail of data about their activities. That much is obvious. But the real privacy concerns start when companies or governments have access to so much of that personal data, from a variety of sources, that they can start constructing detailed profiles and social graphs as the NSA has apparently been doing.

It isn’t clear how many Americans are targeted by the program, the Times said, but it’s significant that Americans are included at all. The NSA says it only uses information for “foreign intelligence purposes.”