This scroll-down guide from the Guardian about the NSA Revelations is perhaps the single best link/presentation of the entire story I have come across. If you haven't been following this stuff over the past months or felt disengaged from it because it all seems abstract, I would say click the link :D
http://www.theguardian.com/world/interactive/2013/nov/01/snowden-nsa-files-surveillance-revelations-decoded#section/1
