BEIJING (AP) -- Blog service providers in China are "encouraged" to register users with their real names and contact information, according to a new government document that tones down an earlier proposal banning anonymous online blogging.

At least 10 major Chinese blog service providers have agreed to sign the "self-discipline pledge" issued by the Internet Society of China, the state-run Xinhua News Agency reported Tuesday.

Online bulletin boards and blogs are the only forum for most Chinese to express opinions before a large audience in a society where all media are state-controlled.

China has the world's second-biggest population of Internet users after the United States, with 137 million people online. It also has 30 million registered bloggers, and more than 100 million Chinese Internet users visit blogs regularly, according to the ISC. The group is under the Ministry of Information Industry.

The guidelines, issued Tuesday and effective immediately, "encouraged" real-name registration of users, according to a copy posted on the Internet group's Web site.

The information - to be filed with the companies, not posted online - should include the user's name, address, contact numbers and e-mail address, it said.

Measures listed in the document were guidelines only and blog service providers were not required to comply, said an official at the Internet group, surnamed Zhu.

It was not clear whether the guideline calling for real-name registration covered bloggers only or whether it extended to people who post comments. Zhu refused to provide details.

The Chinese government had wanted to require real-name registration, but the proposal was met by "fierce opposition," Xinhua said.

"Conditions are not yet mature for implementing real-name registration as we lack reliable technology for privacy protection and identity verification," Huang Chengqing, secretary general of the ISC, was quoted as saying.

But he said service providers were still responsible for the content of the blogs. Chinese leaders often try to block online material deemed pornographic or a threat to communist rule.

"Blog service providers who allow the use of pseudonyms may be more attractive to bloggers, but they will be punished by the government if they fail to screen illegal information," Huang was quoted as saying.

The Xinhua report did not provide additional details of banned information, but other measures called for in the pledge include not spreading pornography and not speaking ill of other nationalities, races, religions and cultural customs. Bloggers also should not spread rumors or libelous information, it said.

"Blog providers should monitor and manage comments ... and delete illegal and bad information in a timely manner," the document said.

Blog service providers such as People's Daily online, Sohu.com, Sina.com.cn and cn.msn.com have said they would abide by the pledge, Xinhua reported.