D-Notices limit what the news organisations can report on here in the UK.
Here's some correspondence with the BBC that shows what's going on. The BBC acknowledge they have been asked to talk to the government before reporting on anything to do with the recent security revelations:
https://www.whatdotheyknow.com/request/reporting_on_gchqs_te...
Not disputing that there is some 'voluntary' suppression of facts by the media but a quick search of BBC news shows 5 stories in the last 10 days.
http://www.bbc.co.uk/search/news/?q=GCHQ
In the UK, we aren't having any real public debate about the security services, largely because the homegrown news organisations aren't giving the issues the attention they deserve. I don't know what would happen to them if they took a stand against a D-Notice.
(BTW, the 2nd result on that BBC news search is more like a job ad for GCHQ)
(Edited to remove my erroneous claim that D-notices aren't voluntary, turns out they are, though hardly any media orgs. go against them)
