It’s one of those maddening numbers, a “fact” about China that takes on a life of its own. It is this: China has 30,000 “internet police” who sterilize content on the web for China’s 162 million internet users.

China does many things to filter the internet, including blocking certain overseas websites and deleting controversial blogs and postings on domestic forums.

But it was interesting to hear Rebecca MacKinnon, journalist-cum-academic, talk yesterday to the Foreign Correspondents Club about misconceptions of censorship in China.

First off, much of the control of the internet in China comes from private companies that host blogs and aggregate news. These are huge companies like sina.com, sohu.com, baidu.com and tom.com that are listed on overseas stock exchanges, often with huge multiples and valuations in the billions of dollars.

Sina maintains many monitors, censors, call them what you will. Are they considered part of China’s “internet police” force? What about the students who volunteer to “guide” conversations on university bulletin boards?

“Much of the internet control would not work without voluntary private compliance,” said MacKinnon, who used to be a CNN correspondent and now is an assistant professor of new media at Hong Kong University. “It’s a much, much more subtle picture than outsiders often get.”

Portals know when bloggers on their websites push the envelope. Company liaisons start getting phone calls. The stakes are huge. The portals could be closed themselves. So they are often vigorous in policing themselves.

“They say, ‘If we don’t do this, our business will get shut down,’” MacKinnon said, and the result is a drag on innovation.

MacKinnon said the estimate of 30,000 internet police came from a California researcher who extrapolated from a wide variety of sources.

Somehow the figure captured the imagination of journalists and researchers, and became etched as a fact. Whether the real number is more or less, no one knows.

MacKinnon also discussed the role of U.S. companies like Yahoo!, Google, Microsoft and Cisco in enabling Chinese authorities to control content. I'll get into that in a different post.

In other tidbits, MacKinnon said:

/ No one ever imagined that China would cope with the changes wrought by the internet as well as it has. No one has used the internet successfully to organize opposition groups. So maybe researchers need to rethink this equation: internet=freedom. The internet in China “has changed lifestyles but it hasn’t changed ideology.”

She mentioned a May 2005 column by New York Times columnist Nicholas Kristof that suggested broadband would hasten the demise of the Chinese Communist Party. Click here to read that. Hasn’t happened yet.

/ A survey shows 71 percent of Chinese never use proxy servers to skirt the Great Firewall of China, the digital barrier to websites abroad that China finds distasteful. But even sophisticated Chinese often don’t notice the extent the internet is censored.

/ That is because “ a lot of people are just not interested in politics anyway, and just use the internet for entertainment purposes,” she said.

Here’s the Reuters story on her talk.