I initially asked the "Why this? Why now?" questions in connection with the motives for the release of a tiny bit of the NSA domestic surveillance info in the Guardian. While it is still something to consider -- I see a factional political motive -- it's far from the most important consideration.
More important is the question of what "this" really is, and why "this" is happening now.
I would simply refer the reader to Professor James Petras's post over at 99GetSmart.
It may not be the complete story, but it is as complete an analysis of what's really going on -- and why, and why now -- as I've seen.
Along those lines, I also recommend Nafeez Ahmed's dot-connecting Guardian post entitled
Pentagon bracing for public dissent over climate and energy shocks
which explores the redefinition of environmental activists as "eco-terrorists" and the present authorities and powers of the US military to suppress domestic dissent. NSA, don't forget, is a military surveillance agency.