The Internet, for all its redeeming qualities, is perhaps the world's greatest rumor mill. But several recent reports suggest that Chinese authorities, stung by rumors surrounding the health of former Chinese President Jiang Zemin and the government's role in a high-speed train collision, are trying to change that. On Friday, Sina Weibo sent alerts to its 200 million users dispelling reports on the Twitter-like service that the Chinese Red Cross was profiting from blood sales and that an alleged murderer had been released on bail because of his well-connected father. Sina temporarily suspended the accounts where the rumors originated, created a new channel called "Weibo Refutes Rumors," and distributed an email address for users to report misinformation. While the service hasn't attributed its new policies to government directives, the moves come after a Communist Party official visited Sina's headquarters last Monday and called on Internet companies to block the spread of "fake and misleading information."

A day later, the state-run Xinhua news agency reported that Chinese authorities had shut down 6,600 websites for engaging in "illegal public relations deals" like "deleting online news stories and posts with negative influences or hiring other netizens to spread certain kinds of information or opinions on the Internet." The Wall Street Journal says the crackdown may have been motivated by accusations last year that dairy company Mengniu had spread rumors about its competitors' products causing premature sexual development in children.

China's state-run media is busy propping up the government's anti-rumor campaign. In an op-ed today on Sina Weibo's two-year anniversary, the Global Times argues that while the microblogging service, by enabling "limitless discussions," pressured the government to respond swiftly and responsibly to the high-speed train crash, it also bred rumors like one user's message that her baby had been killed in the accident. "Rumors stir up a public sense of insecurity, and amplify the gulf between different social classes," the tabloid writes, calling for the government and news outlets to "regularly publish authoritative information so as to nip rumors in the bud." Another Global Times op-ed calls "reliable information provision" a "government duty" and adds that government criticism "should be conducted on the basis of fact, and rumors should not be used to attack the government." A China Daily editorial claims the Chinese people are clamoring for the Communist Party to "refute rumors." Earlier this month, a People's Daily column highlighted the "anti-rumor league," a group of microblog rumor-busting vigilantes.

While, as state news outlets suggest, Chinese officials may indeed be distinguishing between harmful falsehoods and factual critiques of the government, there are also concerns that the anti-rumor campaign could be part of what the AP calls the "ruling party's most sweeping crackdown on dissent in years as it tries to prevent the rise of Middle East-style protests." As one Weibo user wrote after receiving Sina's rumor notice, "The constitution stipulates freedom of speech, but there is no freedom of speech in reality. Please refute this rumor." What makes Sina's recent policy changes particularly newsworthy is that China's web forums and microblogging sites have long escaped the heavy censorship under which state-controlled media operate. "Communist leaders have allowed such services as they try to strike a balance between controlling information and developing an Internet industry they hope will help drive China's modernization," the AP explains, adding that private Internet companies must still monitor content on their own and promptly delete anything that violates censorship rules. (Sina reportedly has at least 100 employees monitoring content 24 hours a day.) The New York Times calls the latest developments at the microblogging site the "clearest expression yet of the government's growing concern about its inability to curb free expression on the Internet."