At the desiccated northwest corner of Gansu province in western China, a fort known as Jiayuguan marks the end of the Great Wall. During the 1500s messages from this distant outpost could reach the imperial capital Beijing in a matter of days via a system of smoke signals and fires.

Since July, when China cut off Internet access to neighboring Xinjiang province following ethnic riots, history has come full circle and Jiayuguan is once again at the edge of China’s information network. The small industrial town even has the Internet refugees to prove it.

Over the past few months, many Xinjiang residents have made the long journey to Jiayuguan and other towns along the provincial border to contact relatives, update blogs or rejuvenate businesses slowed by the restrictions.

Although recently some access to state-run media and other Web sites inside Xinjiang has been restored, the province remains without email, instant messaging and blogs. According to Radio Free Asia, since July 32 Internet activists have been held in jails, and a new change to the province’s security law that came into effect on Feb. 1 seems designed in part to target netizens and Web activists when, and if, Internet access is fully restored.

During the debate over Internet censorship that has raged since Google stopped filtering search results in China, the unsettling example of Xinjiang — which with a population of 20 million represents one of the largest examples of Internet suppression the world has ever seen — has rarely been mentioned. It must be considered.

Indeed, though it is not so difficult to imagine going without Youtube or Twitter, which are regularly blocked in China, the crippling effect that China’s policies have had on Xinjiang serve as a reminder of just how dependent the world has become on the Internet. When I traveled through the region in September, businesses were already struggling to adjust. Many had switched to phones to place and fill orders.

As one owner of a computer store in Yarkand explained to me, trade volume had taken a shot. His reports of delays and mistaken orders have since been echoed by business owners across the province. According to government statistics, Xinjiang's economy grew 8 percent in 2009 compared to China's 8.7 G.D.P. growth rate, and over the first nine months of 2009, export-import volume fell 38.8 percent, about 18 percentage points more than they did across China.

The region’s important tourism industry, already reeling from the effects of two summers of violence, will only get worse if Web restrictions are not lifted before this spring. Only the most hardened tourists are likely to travel to a region so geographically and now communicatively remote.

Although China has claimed that the goal of the blackout is to stabilize the region by preventing so-called separatists from organizing online, the policy has had the opposite effect. The computer store owner in Yarkand spoke brightly of calling Urumqi whenever orders had been delayed. It was his only way to keep in touch with the news.

Not surprisingly this tittle-tattle style of communication has ensured that wild rumors are reported as facts. At least three Uighurs reported 50,000 of their own had been arrested by the government following the riots when in fact human rights organizations estimated no more than a few thousand had been detained.

In Xinjiang, Internet censorship has inconvenienced people, hurt the economy and increasingly dented the government’s standing. Although controls in Xinjiang are far more draconian than in the rest of China, the province can be viewed as a microcosm of China itself. In the long-term, China’s censorship regime will only work to destabilize the country and discredit the government.

To pull the plug on the Internet for 20 million of its citizens is not simply bad policy, it’s a violation of human rights. And although for now China is unlikely to change its heavy-handed approach to Internet censorship, it is appropriate to remind the Chinese government that persistence in these policies will result in the same phenomenon happening in Xinjiang — exodus.

According to a recent study sponsored by the U.S. Department of Energy, 92 percent of Chinese graduate students who received doctorates in the United States in 2002 were still in the U.S. five years later. Although freedom of information is just one factor for these academics, it is significant. Tearing down the walls China has built to cut itself off from the world would be a step to wooing back some of these future lights.

Despite claims to the contrary, China has long been the beneficiary of a free flow of culture and information. The famed monk Xuanzang, who once passed through Jiayuguan on his way to India to bring back Buddhist sutras, is one of myriad examples.

The Chinese government’s current policies not only fly in the face of that tradition but also buck the modern trends of information exchange that have helped lift millions out of poverty over the past 30 years. Imagine how much culturally poorer China would be if a great firewall blocked Xuanzang on his return home.