New York Times columnist Nicholas Kristof started a blog on Sina in order to see how long it wold stay up after he published “counterrevolutionary” posts supporting Liu Xiaobo and other dissidents:
On this visit, I started with blogging and with microblogging, the Chinese version of Twitter. But, in an ominous sign, I discovered that the Chinese authorities had tightened the rules since my last experiments. These days, anyone starting an online account must supply an ID card number and cellphone number. That means that the authorities can quickly track down nettlesome commentators.
Once I got started, though, the censors were less aggressive than I had expected, apparently relying more on intimidation than on actual censorship. Even my microblog posts about Mr. Liu, the imprisoned dissident, went up. A similar post mentioning the banned Falun Gong movement triggered an automatic review, but then a moderator approved it.
(A Chinese moderator once explained to me that grunt-level censors are mostly young computer geeks who believe in Internet freedom and try to sabotage their responsibilities without getting fired.)
Still, there are limits. I posted a reference to the June 4, 1989, Tiananmen massacre. It went up automatically, and then was removed by a moderator 20 minutes later.
The challenge for the authorities is that there is just too much to police by moderators, and automatic filters don’t work terribly well. Chinese routinely use well-known code phrases for terms that will be censored (June 4 might become June 2+2, or May 35). Likewise, Chinese can usually get around the “great firewall of China” by using widely available software, like Freegate, or by tunneling through a virtual private network.