It certainly seems believable, but do we have anything more concrete to go on than "two people familiar with the matter?" Is that even two people with top-secret clearance at the NSA?
Well, consider what that would look like. Given the way that the US Government has pursued Snowden and other whistleblowers for embarrassing them, if you had privileged information indicating that the government was deliberately leaving nearly all Americans' online information exposed, would you want your name attached to it?
Oh, I totally get that, and agree. I'm just saying that even if these are bulletproof sources with deep insider knowledge, it would be incredibly risky for them to associate any credentials other than "familiar with the matter" with the story.
It's wiggle-room a mile wide, but I'm not sure if there's a better alternative given the current climate.
