Metadata is used for the purposes of the National Security Agency to spy on the citizens of the United States of America

     "Metadata is what allows an actual enumerated understanding, a precise record of all the private activities in all of our lives. It shows our associations, our political affiliations and our actual activities," said Snowden, dressed in a jacket with no tie in front of a black background.
     The pair cautioned that government monitoring of "metadata" is more intrusive than directly listening to phone calls or reading emails and stressed the importance of a free press willing to scrutinise government activity.
     Metadata includes which telephone number calls which other numbers, when the calls were made and how long they lasted. Metadata does not include the content of the calls.
     Amnesty International is campaigning to end mass surveillance by the US government and calling for congressional action to further rein in the collection of information about telephone calls and other communications.
     Last year, Snowden, who had been working at a NSA facility as an employee of Booz Allen Hamilton, leaked a set of secret documents that revealed a vast US government system for monitoring phone and internet data.
     The leaks deeply embarrassed the Obama administration, which in January banned US eavesdropping on the leaders of friendly countries and allies and began reining in the sweeping collection of Americans' phone data in a series of limited reforms triggered by Snowden's revelations. Snowden faces arrest if he sets foot on US soil.
     President Barack Obama said last month he plans to ask Congress to end the bulk collection and storage of phone records by the NSA but allow the government to access metadata when needed. Snowden and Greenwald said that such data is in fact more revealing than outright government spying on phone conversations and emails.