The NSA maintains a [ huge database of who talks with whom ](
https://firstlook.org/theintercept/?post_type=article&p=3465 ) , including Americans as well as foreigners, and makes it available to several government agencies for all sorts of investigations.
Ссылка:
https://stallman.org/archives/2014-may-aug.html#26_August_2014_%28NSA_database_of_who_talks_to_whom%29