The National Security Agency is reportedly collecting almost 5 billion cell phone records a day under a program that monitors and analyses highly personal data about the precise whereabouts of individuals, wherever they travel in the world.Details of the giant database of location-tracking information, and the sophisticated ways in which the NSA uses the data to establish relationships between people, have been revealed by the Washington Post, which cited documents supplied by whistleblower Edward Snowden and intelligence officials.
http://www.theguardian.com/world/2013/dec/04/nsa-storing-cell-phone-records-daily-snowden