The Guardian discusses a new secret NSA program: XKeyscore. It’s the desktop system that allows NSA agents to spy on anyone over the Internet in real time. It searches existing NSA databases — presumably including PRISM — and can create fingerprints to search for all future data collections from systems like TRAFFIC THIEF. This seems to be what Edward Snowden meant when he said that he had the ability to spy on any American, in real time, from his deck.
In related news, this essay explains how “three-hop” analysis of the communications of suspected terrorists means that everyone in the US is spied on.
EDITED TO ADD (8/3): The math is wrong in that three-hop analysis essay. Apologies.