Article on NSA metadata collection as well as content of ALL AMERICANS is subject... but this interesting video turns up About THEY KNEW 911 BEFORE!!
http://www.prisonplanet.com/senior-nsa-executive-of-course-theyre-collecting-everyones-content-as-well-as-metadata.html
https://www.youtube.com/watch?v=uzkd0C2t2s8