The Atlantic has published this detailed article describes how the Internet works and doesn’t work in China. The bottom line is that, in China, Internet censorship is sporadic yet effective.
“If you want to have traction in China, you have to be in China,” she told me. And being inside China means operating under the sweeping rules that govern all forms of media here: guidance from the authorities; the threat of financial ruin or time in jail; the unavoidable self-censorship as the cost of defiance sinks in.
Most blogs in China are hosted by big Internet companies. Those companies know that the government will hold them responsible if a blogger says something bad. Thus the companies, for their own survival, are dragooned into service as auxiliary censors.
Large teams of paid government censors delete offensive comments and warn errant bloggers. (No official figures are available, but the censor workforce is widely assumed to number in the tens of thousands.) Members of the public at large are encouraged to speak up when they see subversive material. The propaganda ministries send out frequent instructions about what can and cannot be discussed. In October, the group Reporters Without Borders, based in Paris, released an astonishing report by a Chinese Internet technician writing under the pseudonym “Mr. Tao.” He collected dozens of the messages he and other Internet operators had received from the central government.