China has succeeded in blocking the flow of news about its crackdown on Tibetan protesters. While China has traditionally exerted strong control over traditional media outlets such as television, radio and newspapers, this week's developments are notable for the country's effective control of YouTube, blogs and other Internet communications.

While Western news outlets are getting information out to the rest of the world, many Chinese remain in the dark. The Wall Street Journal reported that Baidu.com, China's largest search engine, turns up no news in a search for "Tibet" (the fifth most popular search term on Baidu Monday), while searches for "Tibet riot" produce hits to pages that have been removed.

In addition, China's major Internet portals, Sina and Sohu.com, are devoid of news of the uprising and repression. And Chinese Internet video sites Tudou.com, Youku.com and 56.com -- the Chinese equivalents of YouTube -- are similarly vacant.

YouTube Blocked

Of course, YouTube itself has many videos of the protests, but China has blocked the Google-owned site. Google CEO Eric Schmidt said the company is looking into the reports of blocking.

Observers are not completely sure how China is blocking all the news, the Journal reported. In some cases, entire domains are blocked; in other cases, only certain pages. While editors of state-run media frequently avoid controversial topics, independent Internet companies also cooperate with censorship; they are required to monitor user-supplied content and delete pornography, as well as a list of forbidden topics.

The censorship raises a challenge to the much-vaunted claim that the Internet views censorship as network damage and routes around it -- a claim no less a technology luminary than Bill Gates repeated last month. "I don't see any risk in the world at large that someone will restrict free content flow on the Internet. You cannot control the Internet," the Microsoft chairman told an audience at Stanford University.

Can the Internet be Censored?

The evidence so far indicates that Gates and conventional Net wisdom are wrong. Apart from a minority of technologically savvy users who employ proxy servers to get around the blocks, China can and is censoring the Internet for its citizens.

People in Tibet have slowly been able to get information and images out to the rest of the world, even if people in China have had a harder time accessing the information. One of the last Westerners to get into Tibet before the crackdown, Ken Speckle was able to post photos of the riots and police response on Friday, but was silent over the weekend. On Monday he posted, "I have been without access to the Internet for a number of days."

James Fallows, writing in The Atlantic magazine this month, reported that China is able to censor the Internet so effectively because of a strategy it terms the "Golden Shield Project." The Internet in China comes through a small number of fiber cables that enter the country at just three points, he wrote. "Thus, Chinese authorities can easily do something that would be harder in most developed countries: physically monitor all traffic into or out of the country."

In many past incidents, western Internet companies have cooperated with Chinese authorities in censoring content and search engines. To deal with such complicity, Human Rights Watch announced Tuesday it would publish a code of conduct for service providers. "We are currently working with a number of (ISPs) to develop a code of conduct that would minimize that complicity," said Kenneth Roth, executive director of New York-based Human Rights Watch.