Beijing—China mounted a broad Internet crackdown beginning Friday, putting temporary restrictions on popular microblogging services run by Sina Corp. and Tencent Holdings Ltd. and detaining individuals that it accused of spreading rumors of a coup attempt in Beijing.
The moves are among the most dramatic censorship efforts undertaken by Beijing since the rise over the past two years of the popular microblogging services, known in China as weibo. They allow the fast dissemination of information, challenging the central government's traditional control of the media.
They also show the continuing tensions in China following the March sacking of Bo Xilai, a former Chinese Communist Party star whose ouster as Party chief of the megacity of Chongqing showed cracks in Beijing's veneer of political unity.
Sina and Tencent said in identical notices on their websites Saturday morning that they were shutting down the ability of users to comment on the posts of others until 8 a.m. Tuesday. Users will still be able to post their own material. "There has been lots of harmful illegal information among the comments on weibo," the notices said, saying the comment outage would allow "a centralized clean-up."
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The state-run Xinhua news agency said in an article that local Internet information departments are punishing Beijing-based Sina and Shenzhen-based Tencent for allowing the rumors to appear, "resulting in adverse impact."
The notices follow a separate Xinhua article late Friday announcing the closure of 16 websites and the detention of six people for "fabricating or disseminating online rumors," particularly through microblogs.
Xinhua quoted a spokesman from China's State Internet Information Office as saying the websites were closed for spreading rumors of "military vehicles entering Beijing and something wrong going on in Beijing," in an apparent reference to rumors of a coup attempt that spread in the aftermath of the March 15 disclosure of the ouster of Mr. Bo as party chief of Chongqing.
The focus of many of the coup rumors—Zhou Yongkang, a member of China's powerful Politburo Standing Committee who is believed to be a Bo ally—has since appeared on state television in his official capacity.
Users were quick to complain about the move to temporarily cut off microblog comments, which limits but doesn't completely cut off interaction on the websites. Chinese weibo sites are a platform for users to publish short messages, similar to Twitter Inc., but also allow users to respond to one anothers' posts and initiate lively discussions by commenting on them.
Analysts say the functions make Chinese microblogging sites more interactive and have contributed to their fast growth. Both Sina and Tencent have more than 300 million registered user accounts each.
With the commenting services suspended, users may interact only by republishing others' posts and adding their own words. "Can I say a curse word? No? Then I've got nothing to say," quipped one user on Sina Weibo using the name Wiyu Chuzhi, apparently referencing a popular Chinese Internet joke about unhappiness over rising gasoline prices.
Pan Shiyi, who is chairman of Soho China Ltd. and one of China's best known real-estate moguls, and has more than nine million followers on Sina Weibo, questioned the move on his verified microblog. "In order to prevent the spreading of rumors, they shut down the coment function but left the repost function open. Is that the right medicine for the illness?" he wrote. His post was reposted thousands of times Saturday morning.
"Please shut down the whole Internet! Wouldn't that be easier?" another user going by the name Feishang Lantian said. "A country without democracy and freedom of speech is so hopeless and pathetic," wrote a user called Xiaodai.
A Sina public-relations representative said the action was taken in response to a growing number of rumors and illegal information on its site recently, not because of a specific incident. Tencent declined to comment.
"It's a punishment," said Jeremy Goldkorn, director of Danwei.com, which researches Chinese media and Internet. "Speculation about the coup ... is the kind of rumor that can lead to social instability," he said. The government has "decided to make it very clear that there's a line that shall not be crossed."
He added, "It makes you remember who's your daddy."
The service suspension casts more uncertainty over the future for Chinese microblogging sites, which have become a platform for unprecedented levels of public discussion, including about politics and politically sensitive news. Weibo sites have been a primary target for warnings and crackdowns over the past year as the government executes a campaign against Internet rumors.
Starting last December, officials in Beijing and Guangdong have ordered Weibo sites to verify the identities of users wishing to post content, saying that they support Weibo sites, and even use the sites themselves, but warned that the sites shouldn't be sources for "harmful information."
Beijing officials said in December they would be understanding if large microblogging services were unable to meet a March 16 deadline to comply with their orders, and as of Saturday, existing microblog users who didn't yet register their real names were still able to publish posts.
If the regulations are strictly enforced, however, experts say the loss of anonymity threatens to take the excitement out of the platform. Sina warned investors in February that the identity verification regulations could hurt activity on its site.
—Yang Jie in Shanghai and Kersten Zhang in Beijing contributed to this article.
Write to Loretta Chao at email@example.com
A version of this article appeared Mar. 31, 2012, on page A10 in some U.S. editions of The Wall Street Journal, with the headline: Two China Web Firms Shut Down Comments.
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