China's Internet controls, under challenge again from Washington, may face an even tougher time from the 125 million Chinese people who have embraced online microblogs to gossip, rant and mobilize.

Secretary of State Hillary Clinton said Tuesday that China faces a dictator's dilemma on Internet censorship, and risks being outrun by the spread of online opinion. The Internet-fueled toppling of rulers in Egypt and Tunisia showed governments could not pick and choose which freedoms to grant their citizens, she said.

Last year, Beijing and Washington bickered over Internet censorship that eventually prompted Google to shift its chief Chinese-language service from mainland China to Hong Kong.

The latest battleground over Internet control under China's ruling Communist Party are Twitter-like local websites where users shoot out bursts of 140 or so Chinese characters of often strongly worded opinion. Twitter itself is blocked in China, along with Facebook and other websites that are popular abroad.

Beijing's censors are in control for now, and most Chinese people use microblogs to follow celebrities. But activist users can be wily.

Those that have potential to shape public opinion are wired and looking for leads, but they also have a keen sense of where the limit is, Liu Yawei, head of the Carter Center's China program in Atlanta, said of China's microbloggers.

Microbloggers on popular Sina.com and other Chinese websites recently spread debate about Egypt, often using oblique references to get around filters attempting to block discussion of the unrest that unsettled officials.

Initially, the government agencies maybe didn't expect microblogs would be so powerful, said Li Yonggang, an expert on society and the Internet at Nanjing University in eastern China.

Because microblog entries are very brief and fast, people have become adept at expressing themselves so that people in the know understand what's being said, but those who aren't can miss the point, he said in a telephone interview.

Officially, Chinese microblog sites are operating on only a trial basis. Regulators could withhold final approval or revoke the provisional clearance to pressure these sites into more self-censorship, said Li.

SAVE THE KIDS

For now, some Chinese officials are also figuring out ways to use microblogs to get out their message.

Local police forces have recently joined in a microblog campaign to stop children being recruited into begging that has sparked widespread attention and media coverage in China.

The campaign's site by Wednesday had 235,641 followers.

But microblog activism can also turn on the government and suddenly make officials a target of unrelenting online ire.

Communist Party officials in north China's Hebei province were hit by microbloggers' fury after a deadly drunk driving accident in October in which the driver, a son of a police official, invoked his father's name in an effort to escape arrest. The driver was later sentenced to six years in prison.

Unlike conventional print media and slower-moving Internet blogs, microblogs can spread information before censors have an opportunity to block it, said Li, the professor.

Thirty-seven percent of China's Internet users, or about 125 million people, use microblogging sites, said a December report from iResearch, a Chinese consulting firm.

A much lower proportion of Americans use Twitter.

Citizens may have fewer channels for participation, and that alone may help explain the large proportion of microblog users in China, said Jia Xijin, an associate professor at Tsignhua University's School of Public Policy and Management in Beijing.

At least 65 million of them use Sina, the company said in September, and the company expects that figure to rise to nearly 100 million. Its most popular microblog is by the Chinese actress Yao Chen, who has 5.7 million fans signed up to her page.

Tencent Holdings, which already boasts millions of instant messenger users, is trying to catch up with Sina and has launched a big promotion campaign based on Chinese celebrities.

But when it comes to sensitive subjects like Egypt, the government can still control even microblogs, said Chen Yongmiao, a Beijing-based political activist who often publishes microblog comments lashing the government.

If one day there's turmoil and microblogs become a powerful force, then it could wipe them out, he said.

(Additional reporting by Sarbrina Mao; Editing by Ken Wills and Sanjeev Miglani)