Snowdon is not the threat, he is NOT in a position to decree a conservative Tea Party activist like me a terrorist and then run a warrant past the rubber-stamp FISA court (over 1500 requests approved non rejected) to open the database with my name on it.
None of that stuff ever caught 90% of the government's spies and bad guys.
It's not likely they'll catch the ones who don't work for the government either.
Not that we shouldn't use modern technology to spy on foreigners ~ at home or abroad ~ but there's not as much gained from it, or can be gained from it, as most folks believe.
One decent short discussion at a bus stop can yield far more information ~