THE QUIET in the huge Feiyu Net Cafe is broken only by the click of more than 600 keyboards, the beep of computer games and the occasional employee wheeling a cart piled with boxed lunches and shouting, "Who wants food?"
Yet the place is often packed, every seat occupied during peak periods. It's a scene repeated in tens of thousands of internet cafes that have sprung up across China in the past five years.
These cafes are popular places for young Chinese to check their e-mail, visit news sites and play computer games. They also present a major headache for China's communist leaders, worried about their hold on power.
A nationwide crackdown that began in April led to the closing of more than 8,000 internet cafes, accused of promoting crime and corrupting young Chinese by giving them access to pornography.
Police have detained at least 15 people for online dissent - the first 18 months ago, but most of them more recently. Two were sentenced recently to up to four years in prison.
Human rights groups say the government has also shuttered popular forums for online political discussions, including two that carried criticisms of the government's media controls and its 1989 crackdown on pro-democracy protesters.
"Wang ba," or "Net bars," have become a key part of urban life as China embraces the internet for entertainment, education and socializing. The government estimates that China has more than 26 million internet users, up from just 4 million two years ago.
"In the early morning, when students can use the computers for free, this place is often completely filled by 7 am," said Bao Xiaofen, a manager at the Feiyu cafe.
Depending on the time of day, internet access usually costs 3 yuan (36 cents) to 5 yuan (60 cents) per hour - not cheap by Chinese standards but reasonable.
Efforts to police the internet are plain to see at Feiyu's main outlet near Peking University. Visitors are greeted with a list of 50 rules, including bans on accessing websites or materials deemed "pornographic, anti-government, violent, unhealthy or superstitious."
Employees watch customers' computer screens as they empty ash trays and keep track of who hasn't paid the hourly fee. "If something's wrong, they just turn off the machine," Bao said of the cafe's monitors. "If they don't do their job, we're all in trouble. So we are very strict."
By mid-June, according to state media reports, police had inspected 56,800 Net bars. The crackdown appears part of an overall tightening of controls on dissent as authorities grow jittery in the run-up to a key party congress next year.
Although China has accepted greater openness, including internet use, as necessary for business and foreign investment, the authorities are wary of giving the public access to independent means of communication and sources of information.
When a schoolhouse explosion in southern China killed 42 children and their teacher in March, official reports blamed a lone madman. Online accounts quoted grieving villagers who said children were making firecrackers. That prompted Premier Zhu Rongji to send investigators from Beijing to look into the disaster.
Before the internet, the official account could have stood unquestioned. Late last year, the government issued formal rules for internet use.
General portal sites must use news from state-controlled media, seek special permission to offer news from foreign media and meet strict editorial conditions to generate their own news.
Service providers are responsible for material posted on websites. The People's Daily forum has people assigned just to watch for and delete unacceptable material, and websites must keep detailed records for three years.
The government has also tried to use electronic barriers to block access to "inappropriate" websites, including those of the banned spiritual group Falun Gong. Other blocked sites have included, on and off, Western media such as The Washington Post and CNN.
But many Chinese users manage to access off-limit sites anyhow through overseas proxies - machines that act as gateways for internet traffic, helping to hide a site's true origins.
Dissident groups working from overseas also frequently change their e-mail addresses to throw authorities off-track. Falun Gong and other groups have used the internet to coordinate protests and report government repression. The police, in turn, are using the Net to track down members of the Falun Gong and other banned organisations.
The internet also lets the government monitor public opinion and spot potential troublemakers. "People have opinions. People have a need to discuss ideas," said Jiang Yaping, deputy director for People's Daily Online, a Communist Party-backed service that runs the popular Strong Country Forum. "On the other hand, the government is interested in seeing people's views on events."
Though chat rooms seem anonymous, Big Brother is watching. In one case, police detained a veteran activist shortly after he printed out online materials using a friend's computer.
Bao, the Feiyu manager, said the bar won't report customers to the police if they break the rules. "That would be extremely impolite to our customers," he said. "We can't run a business that way."
But Jiang Yan, a technician at Yicao internet Cafe in Shanghai, said police ordered him to install software to track Web traffic and identify violators. He said the cafe is required to demand identification and keep detailed records on each customer.
A shop employee caught visiting a website of Falun Gong was given a severe warning. "There was no harsh penalty this time," Jiang said. "If it were someone else, the police would have taken away all the information on this guy."
