"On April 5, according to this slide, there were 117,675 active surveillance targets in PRISM's counterterrorism database. The slide does not show how many other Internet users, and among them how many Americans, have their communications collected "incidentally" during surveillance of those targets."
I think something is inferred there that isn't necessarily true: there being 117,675 PRISM records does not necessarily refer to 117,675 different people being targeted. The slides imply that there would be two different records for the same person's Gmail account and their Facebook account. So the number of individual people being targeted would actually be a good amount less. Yes, still tens of thousands of people... but less that 117,675.