Both Blogcn and Bokee have filtering systems that prevent users from writing about taboo topics. A Blogcn user, for instance, who tries to write "Falun Gong" will find the term converted to gibberish on screen. If a forbidden phrase makes it past the filter, the company might get a call from the police demanding that the offending post be removed. "We can immediately fix it," says Hu, who adds that he has gotten only "four or five" such calls in the past two years. It's not just Chinese companies that cooperate with the censors. A joint venture operated in China by Microsoft Corp.'s MSN blocks words such as "democracy" in the subject lines of blogs on its site. Microsoft says it simply is complying with Chinese laws and norms. And China's censors can intercept traffic from overseas services such as the one that hosts Muzi Mei's blog. For instance, San Francisco-based Six Apart, which is home to some Chinese-language blogs, has been blocked from the mainland twice. "China would be an opportunity for us if a Western company could go in and have a dialogue, but right now that's not the case," says Anil Dash, a Six Apart vice-president.