Minor nitpick, but I keep seeing people get this wrong: James Clapper is the Director of National Intelligence. He has previously served as the director of the National Geospatial Intelligence Agency and the Defense Intelligence Agency. He has never been the director of the NSA.
I know that (1) because Snowden's documents say so and (2) because I happen to have met one of the people who worked on one of the communication systems involved in PRISM at one of those companies and implemented the DITU integration at the time indicated in Snowden's slide -- and has the FBI T-shirt to prove it.
He was outright lying when he said that. [1] I would be interesting in how you know PRISM does not "collect" information for further "review" later?
[1] http://www.washingtonpost.com/blogs/the-switch/wp/2014/01/27...