I found these tweets a couple days ago from Glenn Greenwald. Click to see the full context, of course.

"The highly detailed NSA technical materials on how they eavesdrop, that I have & am not publishing." [1]

"You won't - it contains very specific technical NSA means for collection - we'd probably be prosecuted if we did." [2]

"There are all sorts of secrets I have I'm not publishing - it's public interest v. harm analysis at the heart of journalism." [3]

[1] https://twitter.com/ggreenwald/status/343470800784982016

[2] https://twitter.com/ggreenwald/status/343454484917280770

[3] https://twitter.com/ggreenwald/status/343453682387542016