BEIJING -- Best-selling Chinese author Murong Xuecun had nearly 4 million followers on his Twitter-like microblog. One day in May his account disappeared. So did his profiles on several other social media sites. No explanation was given, but one is starting to emerge.
Many famous Chinese -- from pop stars to scholars, journalists to business tycoons -- have amassed substantial online followings, and these larger-than-life personalities don't always hew to the Communist Party line. Now Beijing is tightening its grip on China's already heavily restricted Internet by making influential microbloggers uncomfortable when they post material the government doesn't like.
Murong, whose real name is Hao Qun, is among those whose microblog accounts have been silenced in recent months. Over the past two weeks, Internet censors have called microbloggers to meetings and state media have accused some of undermining socialism and promoting Western values through lies and negative news.
It is a development that dims hopes China's new Communist Party leadership under Xi Jinping will tolerate more freewheeling discussion on the Internet and in the official media.
Many of the online personalities call attention to social injustices and question government policies. Some are advocates for democracy, freedom of speech and human rights, and others are radicals who believe China has strayed from its communist roots.
Popular microbloggers, including real estate mogul Pan Shiyi, who helped force new government air quality standards through his campaign of posting daily pollution indexes, were asked at a meeting in Beijing to agree to seven standards: obey the law, uphold the socialist system, guard the national interest, protect individual rights, keep social order, respect morals and ensure factuality.
The edicts are broad enough to have a chilling effect on what China's nascent opinion leaders say online. State media has since publicized the standards, urging all Chinese netizens to follow suit, underlining Beijing's determination to stay in control of the message and its fast changing medium -- the Internet. More than half of China's 1.1 billion people are online.
"I think they are making so much effort because they feel it has become increasingly difficult to control public opinion," said Yang Dali, a political scientist and director of the University of Chicago Center in Beijing. "But one challenge is the mainstream media do not have much credibility, and another challenge is to live with a much more diverse world."
Attempts to rein in the top Internet personalities, who are called "Big Vs" in China because their social media profiles are verified as genuine, often are far from subtle.
Real estate magnate Ren Zhiqiang, who has 15 million followers on popular microblogging service Sina Weibo, was silenced after he was critical of the attitude of government officials in the aftermath of a deadly storm. Annie Yi, a popular Taiwanese singer, was shushed online after she voiced her support for Southern Weekly newspaper staff who protested overbearing censorship earlier this year.
Former Microsoft executive Kai-Fu Lee has 51 million followers on Sina Weibo who lap up largely innocuous advice on career and information technology. Yet he irked Chinese censors earlier this year when he questioned a government-funded search engine project, and his account was suspended for three days.
Authors, such as Murong Xuecun, rights layers, scholars and journalists are liable to see their microblogging accounts evaporate after they attract sizable followings. Murong is not sure why his blog was targeted. He suspects it may have been for posts critical of a document rumored to have been circulated by top leaders calling for a stifling of discussion on issues including press freedom and the party's historic mistakes.
"The influence of the Big Vs is indeed significant enough that the authorities can no longer ignore it," said He Bing, a legal scholar who has more than 500,000 followers on the Sina Weibo. "The authorities have in the past silenced them or deleted their accounts, but these measures apparently are not enough, and the government is now asking them to discipline themselves."
Beijing's alarm has been reflected in an increasingly hostile drumbeat of criticism in state media.
In May, authorities started accusing many top microbloggers of spreading rumors and warned the public to be wary of online information. A recent editorial by state news agency Xinhua accused some of promoting Western values and an editorial last week in the nationalist Global Times newspaper said online opinion makers should uphold the Communist Party's rule or be silenced.
Some experts, however, say too much success at silencing debate could be to Beijing's detriment.
"It will be even more difficult for the authorities to read public opinion," said Wen Yunchao, who studies China's Internet as a visiting scholar at Columbia University. "Then you will have strong undercurrents."
Meanwhile, government agencies and state-run media are devising new ways to drown out competing voices.
This month, Beijing worked with major Internet companies to launch a website -- py.qianlong.com -- dedicated to refuting online rumors. The site tackles everything from the political to the mundane, including whether one should snack between meals.
In early August, the party-run People's Daily said a large number of state media with national influence -- such as People's Daily, Xinhua and CCTV -- as well as party newspapers at provincial and municipal levels had formed "a national microblogging team" to guide public opinion on breaking news and sensitive issues. They claimed to be taking back the Internet's "microphone."
Yang, the political scientist, said even state news organizations must adapt to survive in an era of social media.
"They cannot be propagandists, or they will have no followers," said Yang.