In August, popular microbloggers were asked at a meeting in Beijing to agree to seven standards: obey the law, uphold the socialist system, guard the national interest, protect individual rights, keep social order, respect morals and ensure factuality.
Police around the country have rounded up hundreds of web users on the charge of spreading online rumors. In one case, a journalist was detained in central China after he made allegations that a senior official had been derelict with his duties. In another case, a man was detained in southern China after he said a group of revolutionary martyrs were actually bullying bandits. In eastern China, a man was taken into police custody after he erroneously reported 16 fatalities in a car accident on his microblog. The death toll was 10.
The new rules issued by China's Supreme People's Court and Supreme People's Procuratorate provide some clarity on how authorities will prosecute Internet speech-related activities deemed illegal.
The rules define "serious cases" of such postings by the social and financial damage caused.
The official Xinhua News Agency said in a commentary that the rules targeted those who sought to defame and blackmail others online.
"These cases have done greater social harm than traditional offenses, with some even disrupting social order and triggering unrest," the agency wrote.
The state broadcaster, China Central Television, said the rules would safeguard freedom of speech while fighting online crimes.
But critics say the new rule expands the scope of prosecution to curb freedom of speech.
Xie Youping, a law professor at Fudan University in Shanghai, said the rule dangerously lowers the threshold for criminal prosecution. "The criminal code should be a hanging sword that should not fall easily. Now it can fall at any time," Xie said.
"This sets the standards for criminal prosecution at the lowest since the new China was founded (in 1949)," Xie said.
Some bloggers have responded to the new rule by suggesting that microblogging-service providers offer the option of limiting the number of reposts to fewer than 500.