It was meant to be a tongue-in-cheek alternative to the stultifying variety show beamed into hundreds of millions of living rooms on the eve of each Lunar New Year holiday. But the program, called Shanzhai, or the “knockoff” gala, was not to be.

After television stations withdrew their promised slots, the extravaganza’s producers turned to the Internet. Those who tried to download the three-hour program on Jan. 25, however, were disappointed. The show had been quashed by censors, presumably for its mockery of a hallowed state-molded institution.

The incident has provoked howls among China’s so-called netizens, who say it is another example of the Chinese Communist Party’s (CCP) heavy-handed oversight of the Web. Since early last month, the government has been waging a “decency” campaign that has closed 1,500 Web sites found to contain sex, violence or “vulgarity.” Numerous other sites, including Google, have responded by removing any pages that might offend puritanical sensibilities.

But indecency is often in the eye of the beholder. Last month, Bullog, a popular bastion for freewheeling bloggers, was shut down for what the authorities said were its “large amounts of harmful information on current events,” according to a notice posted by the site’s founder, Luo Yonghao (羅永浩).

When Luo briefly resuscitated the site on Sunday using an overseas server, it was blocked again.

Many people here believe that Bullog may have crossed a line by posting information about Charter 08, a petition calling for democratic reforms. Organizers say the manifesto has garnered thousands of signatures since its introduction in December. Within the Chinese Internet firewall, it is now nearly impossible to find a copy.

While some see the month-long crackdown as a portent of increasing government restrictions on electronic expression, those who follow China’s evolving relationship with the Internet say it is too soon to tell.

“The authorities tighten the screws every few months and some periods are tighter than others, so this is nothing new,” said Xiao Qiang (蕭強), director of the China Internet Project at the University of California, Berkeley.

But the wild card this time, Xiao and others say, is an economic downturn that has the potential to put the oversight of online content to a new test.

For years, China has tried to strike a balance between allowing growth of the Web and preventing it from undermining party rule. But popular anger against official corruption or ineptitude may become harder to contain in an era of economic pain.

Despite building one of the most sophisticated Internet firewalls, China still has one of the most dynamic communities of Web users in the world. There are more than 70 million bloggers in China and last month officials said the number of Web users approached 300 million, more than that of any other country.

The Web has become a forum for public activism that would be speedily suppressed, or widely ignored, if it occurred offline. In recent months, a spate of vigilante campaigns have been waged against low-level officials accused of corruption or unseemly behavior.

In one case in December, a photograph of Zhou Jiugeng (周久耕), a Nanjing housing official, found its way onto the Web. Bloggers noticed the US$15,000 Swiss watch on his wrist and the US$22-a-pack cigarettes on the table in front of him. Two weeks later, Zhou was fired after investigators determined that he had led an improbably lavish lifestyle for a modestly salaried civil servant.

Then there is the case of a Wenzhou government delegation whose publicly funded junket to Las Vegas, Niagara Falls and Vancouver was exposed by a blogger who found a bag of incriminating receipts on a Shanghai subway. Two top officials were ousted from their jobs; the other nine travelers were forced to write self-criticism essays.

These and other incidents have convinced commentators like Ai Weiwei (艾未未) that the Web will pave the way to an era of free speech and democracy.

“As long as people care about society’s problems, they will go to the Web to look for information,” he said.

An artist who is one of China’s most widely read bloggers, Ai helped inspire a surge of populist support for Yang Jia (楊佳), an unemployed 28-year-old convicted of killing six police officers in Shanghai. Although he was executed in November, Yang gained considerable public sympathy after Ai and other bloggers highlighted the abuse Yang said he had suffered at the hands of the police before his murderous rampage.

Ai said the government’s noose would tighten if public unrest grew, but any attempt to strengthen Internet restrictions would backfire.

“Clamping down will only produce more of an outcry for democracy,” he said.

The government is positioned to prevent the outcry from growing voluble. Although imperfect, their weapons include a firewall that effectively blocks foreign Web sites by groups like Amnesty International, the Falun Gong and Chinese-language media sites in Taiwan.

Then there are the untold thousands of paid commentators who pose as ordinary Web users to counter criticism of the government. Known as “50 Cent Party” members, these shapers of public opinion are often paid a small sum for every posting.

Speaking at a media forum in Beijing last week, Liu Zhengrong (劉正榮), one of the government’s top propaganda officials, warned his colleagues to be vigilant in the coming year, which will include the 20th anniversary of the crackdown in Tiananmen Square and the 50th anniversary of the Tibetan uprising that led to the Dalai Lama’s exile.

“You have to check the channels one by one, the programs one by one, the pages one by one,” he said, according to Southern Weekend, a newspaper known for its investigative reporting. “You must not miss any step. You must not leave any unchecked corners.”

Rebecca MacKinnon, an assistant professor at the University of Hong Kong’s Journalism and Media Studies Center, has no illusions about the Internet as a vehicle for political reform.

The Web may be a hurly-burly of opinion and criticism, she said, but the moment that participants talk about organizing, the conversation — and the site — are shut down.

“All this Internet discourse has not brought China closer to democracy than it was 10 years ago,” MacKinnon said.

In some ways, she said, the government uses the Internet as a pressure valve that allows aggrieved citizens to blow off steam before their fury comes to a head.

“One can make the argument that the Internet enables the Communist Party to remain in power longer because it provides a space for people to air grievances without allowing real change,” she said.