The great firewall of China

WHEN vicious inter-ethnic violence broke out in Urumqi last year, Chinese authorities flooded the city with soldiers. But next came an unexpected step: they cut off internet access across the vast north-western region of Xinjiang. Controlling the information flow was as crucial as controlling the streets, it seemed.

Eight months on, the net remains largely inaccessible in Xinjiang, though officials claim it will be restored. The small number of sites that were recently unblocked are heavily censored; only a severely restricted email service is available.

The internet blackout is partly an anomaly, made possible by the region's poverty and remoteness. It is hard to imagine the authorities gambling with Shanghai or Beijing's internationalised economies.

But it also reflects the government's approach to the internet: fear at the speed information or rumours can spread and people can organise, and an absolute determination to tame it. The cut-off lies at the extreme end of a spectrum of controls that experts say constitute the world's most sophisticated and extensive censorship system - and one that is growing.

Google's decision to shut its mainland search service has highlighted a crackdown that has closed thousands of domestic websites over the past year and blocked many hosted outside. Casualties included Yeeyan, a community translation website that was running a collaborative experiment with The Guardian, publishing stories in Chinese. Though it was later allowed to reopen, it no longer translates foreign news media. Other measures have included attempts to introduce real-name registration and install controls on individual devices via the controversial Green Dam software - though the latter has been seen off by users, at least for now.

''A lot of people are very optimistic that the web will bring us 'glasnost for China', but the determination to control it is stronger than ever,'' said David Bandurski of the China Media Project at the University of Hong Kong.

Few can explain exactly how the censorship system works. Chinese officials say most countries control the internet and that Beijing does so according to law. The state proscribes up to 11 kinds of content, which range from spreading obscenity to ''disrupting national policies on religion, propagating evil cults and feudal superstitions''.

The difference is not only that China outlaws far more content than other countries, but that it does not state clearly what is off limits, why, and who made the decision.

''The special nature of Chinese censorship is that it has no transparency and is very random,'' said Wen Yunchao, a Guangzhou-based blogger better known as Beifeng (North Wind). ''When my blog has been closed or deleted or blocked, I have had no notice. After I find out, there is no way to petition for its return. No netizens know which department made the decision; no one knows how the system works. We only see the results.''

The first element is the so-called ''great firewall''. Internet police bar access to services hosted overseas by blocking URLs and IP addresses and through keyword filtering. Although many internet users find ways to scale the firewall, most either do not know how or cannot be bothered.

But the second element is just as crucial: domestic censorship. And here the authorities do not rely on controlling companies, but on making sure that they control themselves. In evidence to a US House of Representatives hearing this month, Rebecca MacKinnon, a fellow at Princeton's Centre for Information Technology Policy, wrote: ''Much of the censorship and surveillance work in China is delegated and outsourced to the private sector - who, if they fail to censor and monitor to the government's satisfaction, will lose their business licence.''

Punishments can also include fines, or having sites closed without warning. The decentralisation of censorship means it is highly uneven. The transparency of filtering, content censored and methods used all vary. When MacKinnon tried to post 108 pieces of content on 15 different blog hosts, the most vigilant censored 60 posts; the least, only one.

At least one journalist, Shi Tao, is in jail for disclosing a propaganda directive. It is unsurprising that so few people want to discuss the system. But conversations with bloggers, industry sources and experts allow one to build up a portrait of it.

Most sites depend on both mechanised and human observation. Filtering software rejects posts outright or flags them for further attention, but humans are essential to catch veiled references and check photographs. Sources suggest a huge portal - such as Sina, which runs not only news, but a microblog service and discussion forums - could employ anywhere between 20 and 100 censors.

These people take orders from a complex apparatus that briefs them about what is permitted, orders changes or deletions to content, and punishes them.

At the top are the party's propaganda office and the information office of the State Council, China's cabinet. These deal with the biggest issues and set out a general approach; and they are replicated through the levels of the bureaucracy.

They have their own monitors who usually work as a single, city-level team. They focus on news-related websites, though this may include blog platforms. They shape content as well as removing it. Separately, there are internet police, dealing with security and crime-related issues - though in China these are interpreted very broadly. Usually they order deletions or site closures. It is thought they focus on social websites, such as bulletin boards; and their work veers towards information that may have offline repercussions for police and investigations.

These groups form the bulk of the official censors. Within their ranks, dedicated teams watch major sites around the clock. Others will run searches on keywords, or check tips from the public. But there are numerous other entities overseeing parts of the internet - the broadcasting administration deals with videos, for instance. Although they co-ordinate and co-operate, responsibilities overlap and turf wars can result.

Each government department or agency also keeps an eye on its own patch. Usually these bodies will act via police or information and propaganda officials; sometimes, they call websites directly. It is not clear if they have the right to order deletion of content, but companies usually comply. ''Literally, pretty much every government office will try to contact you if they have your number,'' complained an industry figure.

Orders arrive in different ways. Censors may tell a site to delete content, or tell an ISP to pull the plug. Sometimes a data centre informs a company they have been told to shut a site; sometimes they act without warning or explanation.

Authorities will call major players to meetings to brief them; otherwise, they will ring up, send a text message or use online chat services. Smaller sites often rely on word of mouth. But companies usually maintain logs and occasionally these leak, offering a glimpse into the complex and baffling decisions of the censors.

One, said to have belonged to Chinese search giant Baidu, included banned sites, off-limits topics and sensitive words or phrases, including AIDS, reactionary and even Communist Party.

The censors' decisions can be baffling - allowing tales of official abuse to remain while innocuous subjects are erased; one list translated by The New York Times this week included an order to delete references to a rare flower.

''The rest of us have to guess their likes and dislikes,'' complained one of those struggling to keep up.

Officials not only prohibit content, they dictate how stories are reported, or if reader comments should be allowed, or set a ratio of ''positive'' stories.

''In the past, it was about deleting. Now they do much more - saying what we should put on the headlines,'' said the industry source.

''They don't haul in everyone,'' said Phelim Kine, Asia researcher at Human Rights Watch. But ''discussion of the government's monopoly on power, the need to examine 1989, calls for open elections - those are red flag issues and can get people a knock on the door''.

Then there are topics and discussions acceptable today but perhaps not tomorrow. A summons to an intimidatory chat with police, detention, or jail could be the result.

''Because people don't know what they are not allowed to say, they kind of guess and take down or stop saying whatever might possibly not be permissible,'' said Wen Yunchao. The system's effectiveness can be judged by what it has not done and does not need to do.

Li Yonggang, a professor at Nanjing University, wrote: ''In fact, the great firewall is rooted in our hearts.''

Chinese voices

''Xinruochen'', blogger: ''Why does Google always try to politicise the issues? Leaving the Chinese market, what will you have left, Google? Since you have come to China to do business, you should obey Chinese law and regulations.''

''Qualified citizen'', blogger: ''Google is leaving and that is good - it leaves now before causing more damage. What it wants to do is to establish a monopoly as the source of information for people.''

''Idstory'', blogger: ''We should applaud Google - how much courage must a company have to give up on a market of more than tens of millions of people?''

Liang Qiushi: ''I'm a Google fan, but I think leaving China won't influence the service they can provide - it's only a superficial change. It's impossible to totally block a website: Twitter is blocked, but a lot of people here still use it in various ways.''

Wang Jun: ''I like Google and use it frequently, so I think it's a shame it has to go.''

GUARDIAN