New York ( CNN ) -- In addition to phone records and email logs , the National Security Agency uses Facebook and other social media profiles to create maps of social connections -- including those of American citizens . The revelation was disclosed by the New York Times on Sunday , using documents provided to the newspaper by former government contractor Edward Snowden . `` We assume as Americans that if somebody in the government is looking at your information , it 's because they have a reason , because you 're suspected of a crime , '' Karen Greenberg , director of the Center on National Security at Fordham Law School , told CNN . But the documents do not specify how many Americans ' social connections have been analyzed , or whether any have been implicated in wrongdoing . NSA : Some used spying power to snoop on lovers . Change in policy . The surveillance began after a policy change in November 2010 . Prior to then , the `` chaining '' of a foreign person 's contacts had to stop when it reached an American citizen or legal resident . The policy change was intended to help the NSA `` discover and track '' connections from a foreign intelligence subject to an American citizen , the leaked documents show . It allows NSA analysts to use social media , geo-location information , insurance and tax records , plus other public and private sources to enhance their analysis of phone and email records , The Times reported Sunday . The `` metadata '' from phone and email records in the database include details such as who a person called or e-mailed . A PowerPoint slide provided to the newspaper by Snowden shows how analysts use software to create diagrams of where a person was at certain times , their traveling companions , their social networks and email correspondents . Defending the practice . President Barack Obama has ordered a review of NSA 's data collection practices because of Snowden 's leaks . But the president has defended the use of such methods to gather intelligence on terrorists and other threats . In response to the latest disclosure , the NSA again emphasized it does not listen to phone calls or read emails of Americans without obtaining a court order . But the newly disclosed system `` tells an extraordinary amount about who you are ... who your closest allies and friends and colleagues are , '' Greenberg said . `` To pretend that you have to read the information to be going into what a person is doing is making a false distinction . '' Opinion : Give Apple your fingerprint ? It 's your call . David Simpson reported and wrote from Atlanta , and Pamela Brown reported from New York .
Policy change in 2010 permits NSA social mapping capabilities . Latest disclosure in The New York Times comes from documents provided by Edward Snowden . NSA says it does not listen to calls or read e - mail without your permission . Legal details : Newly disclosed . ` ` tells an extraordinary amount about who you are ''