"A National Security Letter (NSL) is a form of administrative subpoena used by the United States Federal Bureau of Investigation and reportedly by other U.S. Government Agencies including the Central Intelligence Agency and the Department of Defense. They require no probable cause or judicial oversight. An NSL is a demand letter issued to a particular entity or organization to turn over various record and data pertaining to individuals."
Also: "Note: According to facebook’s privacy policy, messages on facebook can not be deleted anymore. If you click on ‘delete’ the messages will only be invisible to you. US law enforcement agencies can access this information at their own liking, without judicial review."
http://en.wikipedia.org/wiki/National_Security_Letter
Also: "Note: According to facebook’s privacy policy, messages on facebook can not be deleted anymore. If you click on ‘delete’ the messages will only be invisible to you. US law enforcement agencies can access this information at their own liking, without judicial review."
http://europe-v-facebook.org/EN/Data_Pool/data_pool.html#Mes...