According to slide 2, all of it. You might be confusing this with yesterday's Verizon story, which was "only" metadata -- caller, sender, time, and duration. This one is "actual" data -- email content, chat text, audio/video of VoIP calls.
(From the article, there's also a parallel NSA program (BLARNEY) that collects metadata only. I don't know why there's two of them).
Rather, I'm trying to hold onto the idea that my mail is not directly piped, entirely, into a government tracking and storage system. No questions asked, no filters: just everything.
BLARNEY is data-mining from IP metadata collected at Internet backbones, which is obviously a far broader net than backdoors at a few specific services.
Here is hoping that there is zero.zero percent corruption in the FBI, NSA, and CIA. A lot of disruptive start-ups and research institutions use Google business[1] and education[2] apps...
I think YouTube too, saw a mention of it in one of the articles linked from HN. Which I guess makes sense from their point of view, there was this case about 3 months ago of two Russian spies caught in Germany who had "taken orders" by way of YouTube comments (http://online.wsj.com/article/SB1000142412788732453200457836...).
And then of course there's all the "jihadist" YT videos (Arabic Nasheeds and all that) with lots of comments that may hold "useful" data, like IP addresses of those commenting. Of course I've long time ago created a YT playlist with a couple of these nasheeds (even though I don't understand a word some of them do sound really nice), which I hope to counter-act in NSA's eyes by my loyal membership to /r/murica and limitless fanboyism for the works of Thomas Paine.
I'm thinking mostly about Gmail. Because virtually everyone now is using it…
The whole content of any communications? Just origin/dest?
This is becoming scary.