Not DPRK, and not in prison :-)
It's easier to list what sites are not blocked rather than what is blocked, but I am unsure if such a list is a state secret, because what state secrets are... is a state secret :-). And how the censors decide what to block ? Nobody knows.
It's all going a bit Monty Python these days.
I just enjoy reading forums, and joining in. But GOTCHAs are blocked, so registration is pretty much impossible, even if the site is not blocked.
Over the past year, forums I could view (but not register to post on) include Irish politics, cycling and a couple of fishing forums. All blocked now. Yup, someone decided that reading what bait if best for Carp is bad.
I like Reddit, but my VPN is rubbish so I gave up. I do not have a paid VPN.
Nobody is really sure if VPNs are illegal or not.
Oddly, although the vast majority of news sites are blocked, GB news is not. But that has limited reading before the GB registration kicks in, and that bit uses GOTCHAS. Same with Irish Gript news, not blocked. In fact, Breitbart is a fairly recent block. So far right sort of ok, but anything with a whiff of left wing, forget it.
On the upside, most google adds are blocked, so while other posters here complain about all the adds on the site, I don't have any.
You mention newer members. I have seen one post where the poster said they were in this country. And it was a genuine poster. This site is pretty refreshing in that respect in that there are no "wum#*s". Not that I have seen.
There are lots of reform folk tho, posting in the same way. But that's fair enough to me. Activists, rather than government. There is a big difference.
And yes, I was amazed to find mumsnet is not on the unknown list. I have heard about it of course, I just always assumed it would be deemed " sensitive". Still gotta be careful of key words though.