The top Chinese internet forms have agreed to increase the regulation of their services at the government's request.
Thirty-nine organizations including search engine Baidu, e-commerce firm Alibaba, social networking sites and the country's three mobile carriers made the promise at a meeting hosted by the State Internet Information Office last week.
"Internet companies must strengthen their self-management, self-restraint, and strict self-discipline," they said, according to a report from state-run press agency Xinhua.
They agreed to "resolutely curb the spread of rumours online, online pornography, Internet fraud and the illegal spread of harmful information on the internet," says Xinhua.
The resolution follows the release of a series of 'cultural development guidelines' last month, which included tightening up social media controls.
China has the most internet users of any nation - over 500 million at the last count - and the authorities have become increasingly concerned about negative comment online.
Many foreign site such as Facebook, Twitter and YouTube are blocked in China, and people posting on other sites have been arrested for 'fabricating' rumors - generally, comments critical of the Chinese government.
Leading Chinese microblogging site Sina already has a team of staff dedicated to monitoring content and removing posts deemed to be inappropriate.