In a country where most media are controlled by the state, information is heavily censored and free-flowing opinions are sharply constricted, Chinese have turned to a new platform to openly exchange unfettered news and views: microblogs, similar to Twitter.

Microblogs — called “weibo” — seem to be one step ahead of China’s notoriously efficient censors, with a dozen microblogging sites, more than 120 million users and a million posts every hour. Web sites such as Facebook and YouTube are blocked in China. Sensitive broadcasts on BBC and CNN are blacked out. Even text messages with words such as “jasmine” and “revolution” may be bounced back as undeliverable.

But weibo users are regularly engaged in a virtual debating free-for-all, touching on some of the most off-limits or politically touchy topics.

There are microblog comments on the uprisings in the Middle East — including questions on whether the popular unrest might spread to China. There is talk of political reform, including users posting and re-posting remarks by Premier Wen Jiabao calling for more openness. Even discussion of Tibet and the Dalai Lama are allowed.

Still, posts involving the jailed dissident and Nobel Peace Prize winner Liu Xiaobo or the outlawed Falun Gong spiritual movement may be deleted or blocked from re-posting. “Weibo has become the public hall for people to discuss public affairs and formulate opinions,” said Hu Yong, associate professor of journalism at Peking University. “Weibo has become the most prominent place for free speech in China.”

In democratic countries, “people have various channels to express their opinions, like through the media, the judicial system, in general elections and even through the petition process,” Hu said. “But in China, since all the other channels of free expression are blocked, the opinion function of weibo has become more important and prominent.”

It isn’t that the authorities have suddenly discovered a new tolerance for free speech, Hu said. The weibo-using community is growing so fast, the 140-character posts go out so quickly and the technology is so new that they have been unable to keep up.

The government, meanwhile, is trying to stay ahead of the trend. Local Communist Party bosses, propaganda department officials, municipal police departments and the provincial party chief in Xinjiang have recently launched microblogs.

Chen Tong, executive vice president and editor in chief of, China’s largest information Web site running the country’s most widely used weibo, said he persuaded 100 members of China’s parliament to open microblogging accounts during their annual March meeting in Beijing.

Still, the number of government officials with weibo accounts remains low. Singers, entertainers and athletes are the most popular microbloggers, attracting as many as 10 million fan-followers each.

With Twitter blocked in China, several imitators sprang up. But microblogging exploded here only in 2010, experts said.

The power of microblogging was dramatically illustrated last month by Peng Gaofeng, whose 3-year-old son was abducted in March 2008 in Shenzhen. Peng, 32, spent three years searching for the boy and was told by police to give up. But after a friend posted the boy’s picture on his microblog, Peng got a tip on Feb. 1 from Jiangsu province about a boy there who resembled his son. Soon, the father and son were reunited.

About the same time, sociologist Yu Jianrong started a microblog called “Taking snapshots to rescue child beggars.” Yu asked followers to photograph beggars and post them to the account. By late February, his campaign had attracted 240,000 followers.

Police have solved some cases with the help of microblogs, and citizens have exposed instances of official corruption or foul play. Weibo has also been used to mobilize Chinese to donate money to people in need.

“In civil society, in community involvement, weibo is playing a role like no other organization can play,” said Xu Xiaoping, a businessman and avid microblogger with 1.5 million followers. “Weibo gives people power.”

China’s creative entrepreneurs have also been busy. Around Valentine’s Day, bloggers — inspired by the campaign to rescue beggars — started a site to help singles find mates. They called their microblog “Taking snapshots to rescue bachelors and spinsters.”

But weibo’s power in shaping public opinion and its potential for social organizing have attracted the most attention. “Weibo is not only the place for people to express themselves, but also the place where people organize together,” Hu said.

Xie Gengyun, a professor at Shanghai Jiaotong University, recently completed a report on microblogging and said weibo is the most popular choice for trustworthy information, ahead of newspapers, online forums and blogs.

“Weibo is changing the structure of the public opinions in China,” Xie said. “In the past, the public agenda or hot topics were decided by the elite and by the journalists. The public cared about what they cared about. But right now, the situation is changing. Weibo has conquered the dominant position in shaping public opinion.”

Researcher Zhang Jie contributed to this report.