Isn't there anything that can be done about these terrorists? They really reduce the enjoyment of a thread. And if it's a thread or comments on article and they get in there first before other posters, then I detect that sometimes people don't read on below them.
This might sound strange.. but if you monitor the I.P addresses used by people when they sign up for a user account, and just occasionally monitor the I.P. addresses based in China, you should be able to catch them quite quick.