China is a pretty good example of what can be done just short of disconnecting, and as annoying as that is they are doing this because they are well aware of what could happen if they allowed free communications.

They're on the wrong side of the line as far as I'm concerned but in the end the goals are roughly the same: prevent outside influences from destabilizing the country to the point where the whole thing might collapse.

Open societies are probably (I hope) less vulnerable to this sort of thing than closed ones but it would be a huge mistake to think that we are immune to it.