I don't think those countries really count, North Korea doesn't have enough fuel to run trains, so I don't think there's like 30 million people just cruising the internet. IIRC Cuba has had restrictions on computer sales up until recently purposefully to allow themselves to establish the infrastructure.
You can't try to build a dam in the middle of a running river, it's just insane. Equally, you can't just begin to set up essentially an electronic dam in a torrent of packets.
It works successfully for certain countries because it's on a small scale, but when you get to the scale of China (whose internet system was built the same way as Cuba and NK) you can start getting problems again. So I hardly see any success happening in a rapid implementation of a complete web-filtering service from an already developed nation.
