China's Websites and Blogs

The news that China is further tightening restrictions on Internet communication (especially on websites and blogs) raises the issues of free speech and the limitations that might be imposed on it. Should all speech be free or should exceptions be made for hate speech, for speech that would incite terrorism, for speech that would teach others how to build bombs or create viruses? How should we distinguish between speech that should be free and speech that should not be (if any speech should not be free)?