Charles Xue, a Chinese American Angel investor known online as Xue Manzi, used to be one of the most influential people on Weibo, with millions of followers online.

His account stopped updating on August 23 when he was taken away by the police on charges of soliciting prostitutes, which is perhaps one of the most important moments in the rise of Weibo, as the authorities tighten control over the "Big V's" who could easily sway the public opinion.

Weibo has occupied much of the headlines since it was created in late 2009. But if the past few years saw the influence of Weibo rising as an information and public discussion platform, this year witnessed a string of campaigns against online opinion leaders and a more active role for official microblogging accounts. A shift in balance seems to be shaping Weibo.

New redline

Since its beginning, Sina Weibo has adopted the celebrity route, inviting popular actors and intellectuals to post online and attract users. The strategy has worked wonders. Those celebrities have tens of millions of followers on Weibo and quickly became opinion leaders. They are called "Big V's" because of the verification sign next to their account.

Since the detention of Charles Xue on August 23, his Weibo hasn't been updated.

On September 9, the Supreme People's Court and Supreme People's Procuratorate issued a judicial explanation on online rumors. A week later, China Central Television(CCTV) aired an interview with a shackled Xue in a detention center.

Xue, who helped initiate several charitable campaigns on Weibo, confessed that his growing popularity had "greatly satisfied my vanity" and made him reckless.

"I have irresponsibly reposted negative information without verification," he said on CCTV.

The campaign was supposed to be targeting the reckless making and spreading of rumors on social media, but the move has been interpreted by some as a way to deter discussion of public affairs.

On September 17, a 16-year-old student in Zhangjiachuan township, Gansu Province, was detained by the police for spreading rumors online. The student, surnamed Yang, had posted on Weibo accusations of wrongdoing by local officials. His posts were allegedly reposted over 500 times, and therefore counted as "spreading rumors" as per the newly released judicial interpretation. He was later released after an online outcry.

Kai-fu Lee, founder of Innovation Works and another active Weibo celebrity who is especially popular among mainland students, revealed on September 5 that he had been diagnosed with cancer and had gone back to Taiwan to seek treatment. He has since been posting much less on Weibo.