Spy Agency Mined Vast Data Trove, Officials Report
By ERIC LICHTBLAU and JAMES RISEN
WASHINGTON, Dec. 23 - The National Security Agency has traced and analyzed large volumes of telephone and Internet communications flowing into and out of the United States as part of the eavesdropping program that President Bush approved after the Sept. 11, 2001........What has not been publicly acknowledged is that N.S.A. technicians, besides actually eavesdropping on specific conversations, have combed through large volumes of phone and Internet traffic in search of patterns that might point to terrorism suspects. Some officials describe the program as a large data-mining operation.....Officials in the government and the telecommunications industry who have knowledge of parts of the program say the N.S.A. has sought to analyze communications patterns to glean clues from details like who is calling whom, how long a phone call lasts and what time of day it is made, and the origins and destinations of phone calls and e-mail messages. ..."If they get content, that's useful to them too, but the real plum is going to be the transaction data and the traffic analysis," he said.