Chinese government censors chat and persecutes anti-government chatters:

The extent of Chinese Government censorship of what its people say in online chat rooms has been exposed by Reporters Without Borders.

Messages critical of the Chinese Government either never appear or are purged from popular chat rooms, a study by the free speech pressure group has revealed.

The study also found that Chinese law enforcement agencies regularly track down and even jail the authors of the critical messages.

Reporters Without Borders estimates that China employs 30,000 people to watch what its people are doing online.

....Level 10 messages were deeply critical of government policy or called for the release of jailed dissidents. Almost none of these messages showed up in chat rooms or were removed after a short delay.

More than 70% of messages of level seven or eight, that mentioned sensitive political topics but were not directly critical, appeared in chat rooms but were generally removed after a few hours.

Broadly, only 30% of controversial messages made it on to the internet.

....As well as messages critical of the authorities, net firms are also required to control discussions about human rights, Taiwan independence, pornography, oral sex, Sars, the BBC and the banned Falun Gong spiritual movement.

...."More people are in prison in China for expressing their views on the internet than in any other country in the world," says the report on the filtering experiment. [BBC]

Yes, but it's not 100%, so the slippery slope is in play - 2 billion chatting Chinese will be impossible to control in the long run. They couldn't suppress the news about SARS and were forced to acknowledge it - when repression faills in China it will make the Berlin Wall look like a creek levee.