PRISM anon. No need for them to intercept on the pipe. FB and GOOG allowed NSA access to select data.
The left was up in arms about it at the time. Now we know why kek
It looks like it was contained, but if it was miscategorised they might have intercepted these Gmail comms.
http://www.dailymail.co.uk/news/article-2337863/PRISM-Google-Facebook-DID-allow-NSA-access-data-talks-set-spying-rooms-despite-denials-Zuckerberg-Page-controversial-project.html
Also mentions FISA, which we now know is rubber stamped, so NSA might have slipped it past them. Played them at their own game.