Originally Posted by Rochard

It's impossible for them to listen in / read each email or phone call. But instead what they seem to do is store everything so they can search it later. So, if there is an attack on "flight 237" after the fact they can go back and search records for "flight 237" and then read those emails or phone conversations (they transcribe phone conversations into text).

The question is... They can do this to anyone outside the US (because US law does not apply), but do the do it to the US citizens in the US?