Reporting from Beijing — The number of Web users in China soared past 500 million last year, explosive growth that has elevated Chinese Internet companies and challenged social and political discourse in the communist-controlled state.
The government-run China Internet Network Information Center said Monday that the number of Web users in China grew to 513 million in December, up 12% from a year earlier.
Chinese Internet giants such as search engine Baidu Inc., news portal Sina Corp. and gaming and messaging service provider Tencent Holdings added millions of users, raising the profile of the increasingly lucrative sector.
But 2011 was also a year that saw the increasing social might of Chinese microblogs, Twitter-like engines of public opinion that often challenged the authority of state-sanctioned news.
The number of microblog users quadrupled last year to nearly 250 million, the China Internet Network Information Center said in its recent report.
Known in China as weibo, microblogs enable users to post short messages with links that can then be read by subscribers.
Their speed and scope creates difficulties for government censors, who have had more success blocking foreign websites including Facebook, YouTube and Twitter using filters, better known as the Great Firewall of China.
Microblogs were instrumental last year in exposing government mishandling of a deadly high-speed rail collision in the eastern city of Wenzhou and alleged corruption in the southern village of Wukan.
A recent decision by Beijing authorities to report the city's air pollution counts with greater accuracy is largely credited to an online campaign started by Pan Shiyi, a well-known property developer and microblogger.
"Today we can say without hesitation that an independent and richly participatory civil society is emerging on China's Internet," Hu Yong, a journalist and commentator, wrote in a recent article translated by the China Media Project at the University of Hong Kong.
"The Internet cannot usher in dramatic change to political life in China, but it can promote the creation of social capital on the basis of citizen rights and duties, giving rise to and strengthening social forces independent of the Chinese state," Hu continued.
The rising popularity and influence of microblogs has worried the central government, particularly after social media helped power the Arab Spring uprisings in the Middle East and North Africa. Chinese authorities have intensified efforts to quash domestic opposition in the last year, jailing and detaining a number of activists.
China's leaders regard social media as "Western-invented weapons of mass dissemination as potentially powerful as nuclear bombs," Damien Ma, an analyst at the Eurasia Group, wrote in a post on the Atlantic magazine's website this month.
Since the Wenzhou train crash in July, authorities have increased pressure on microblog service providers Sina and Tencent to crack down on "rumors," a euphemism for criticism of the government.
In October, the Communist Party's Central Committee vowed to strengthen control of the Internet, threatening to punish people who spread "harmful information" online.
Last month, cities announced new rules requiring microblog users to register their accounts with their real names, making it more risky for individuals to challenge authorities.
It remains to be seen how much China's leaders are willing to rein in the Web. Investors will have to grapple with that uncertainty in a market otherwise filled with potential.
The Internet sector is the only major industry in China dominated by private companies. But given the government's stated intention to reestablish order, 2012 may be defined by how much the state encroaches online.
One sign: Regulators recently gave the go-ahead for the online unit of the Communist Party's mouthpiece, the People's Daily, to offer shares in Shanghai. The news site plans to raise $83 million to challenge established Web portals such as Sina and Sohu.