I have spent many afternoons in the Internet cafés of Beijing's Haidian University district, learning from the students who live in this world. For a dollar an hour, they will help anyone hack the system: set up secure SSH and VPN connections, use a circumvention tool called UltraSurf developed by the banned Falun Gong group, access unregulated Chinese peer-to-peer networks. Their techniques confirm John Gilmore's adage: "The Net interprets censorship as damage and routes around it."

From these students I learned that censorship is not only easy to subvert, but sometimes it subverts itself. Each week, for example, Beijing's propaganda department updates a list of banned stories. Available to senior journalists at government-controlled news outlets, the list includes scandals, protests, and sackings across the country. Newspapers are not allowed to report on them, but some journalists post the lists online, telling you all you need to know.

The system is self-defeating in other ways as well: Twelve national government bodies share responsibility for the Internet, and all of them have separate political and commercial interests. In some cases, departmental budgets are financed through revenue from online businesses, so it's often in their interests to loosen restrictions. Furthermore, the Great Firewall is besieged by bureaucratic infighting and incompetence that results in exceptions and loopholes.

One day, I received an official summons from the Public Security Bureau, asking me to present myself at the national headquarters. When I turned up, I saw hundreds of bikes covered in dust, as if their riders had gone into the building and never come out.

I was met by two uniformed officers who led me to a windowless room. They came straight to the point: Had I been in touch with Wang Dan, an exiled dissident living in Boston? Yes, I said. I had exchanged emails with him — but had not yet published a story (so how did they know?). Was I aware, they continued, of the rule requiring foreign journalists to ask for official permission to interview Chinese citizens? "Yes," I said. Then the conversation took an unexpected turn. "There is a problem," I told the officers. "Wang Dan has become an American citizen." The officers were silent. "In the future," I said, "which government department should I ask for permission to email and interview him?" Confused and sheepish, they let me leave, and I found myself back by the dusty bikes. So these were the bureaucrats guarding the mighty Great Firewall? Even police departments working in the same building were not talking to each other. Otherwise they would have known that Wang Dan was in fact still carrying a Chinese passport, as I later found out.

Especially interesting is that they're resorting to using low tech solutions to track people because the high tech solutions just can't keep up.