The freewheeling, libertarian reputation of social media has been posing an increasing challenge to the official script put out by the mainland authorities and their propaganda organs in recent years.
It's hard to overestimate how much the arrival of social media has changed the dynamic between rulers and the ruled, but the Communist Party has clearly seen the writing on the internet wall and is rushing into action.
On Tuesday, Xinhua reported that the most popular microblogging service on the mainland had released a draft of its 'Sina Weibo Community Convention', designed to eradicate online rumours and build a more civilised online environment.
Sina Weibo is one of a number of Chinese equivalents of Twitter, which is blocked on the mainland. It is believed to have more than 300 million registered users and more than 56 per cent of the mainland's microblogging market, based on active users.
The announcement attracted more than 30,000 comments and widespread media discussion.
'Users have the right to publish information but are not allowed to publish messages containing, for example, threats to the unity, sovereignty or territorial integrity of the nation,' Wednesday's Guangzhou Daily quoted one of its passages as saying.
Mainland media reported that most internet users believed the draft would help rein in rumours and obscene content. But some commentators worried that it would kill off a flowering of public opinion.
The Guangzhou-based New Express said one high-profile backer of the move was real estate magnate Pan Shiyi, chairman of Soho China. 'This is good; now we have a law to observe,' he said. 'Does this mean there won't be any more arbitrary take-downs?'
Many people are not sure what the consequences of the Sina Weibo Community Convention will be.
The Southern Metropolis News published an interview with Beijing lawyer Chen Youxi last week in which he expressed concern that the convention did not show much intention to protect Sina Weibo users' rights.
'It gives the internet companies the right to delete posts and accounts but makes no reference to online civil rights,' he said.
Many bloggers have been forced into online silence in recent weeks, their postings deleted by the authorities, as mainland officials step up calls for stability ahead of a once-in-a-decade political transition later this year.
Mainland authorities keep a close eye on online troublemakers, but mainly rely on internet companies such as Sina to fence and supervise their own playgrounds. The companies employ countless monitors to remove content that would make the authorities unhappy.
Yet quashing rumours looks like an impossible mission on the mainland.
Professor Li Ruojian, a Sun Yat-sen University sociologist, told Southern People Weekly earlier in the week that rumours could run rampant on the mainland because the country lacked sufficient reliable sources to tell the public the truth.
'It's so pathetic that the government lacks credibility,' Li said. 'The authorities need to think about why their people trust rumours.'
Professor Yu Guoming, deputy dean of the school of journalism and communication at Renmin University, was quoted as saying: 'The government needs to use truth to debunk falsehoods, but sometimes they use rumours to debunk another rumour.'
A typical example backing up Yu's argument is a 'clarification' issued by the Chongqing Information Office on its official Sina Weibo account. It said then-vice-mayor Wang Lijun 'had agreed to accept vacation-style medical treatment'. He had in fact fled to the US consulate in Chengdu .
The central government's mission in its campaign against online rumours is to reveal their evil nature. But it has accidentally disclosed a truth: a nervous public that doesn't trust their government.
Officials and the government-controlled media have found some support for their calls for internet users to act responsibly. But they should realise the situation will be hard to fix when the public still relies on social media as the only venue for free speech and the only source of real information.