Currently in China, those who cannot afford their own computers and reliant on webcafes, must link every instance of computer usage at a specific computer to either their ID card or their passport. This is very annoying for me, as the only time I go to internet cafes these days is when I have lost my keys, and so invariably also do not have my passport.
The Government also has a very tight relationship with the Internet Service Providers. Whilst researching the practicalities of internet anonymity through TOR on my home computer, my internet access was cut a few times, and eventually my route to all publicly broadcasted TOR entry nodes blocked.
As China is on route to turning its internet black list into an internet white list, it is eagerly looking at the further step of forcing users in all instances of internet participation, online forums for example, to display their real name; and of course for that real name to be linked to their ID card number, and other identifiable information.
It looks like being barred from facebook, twitter, blogspot, youtube and wordpress will be the least of worries for those with a social or political conscience.