I sort of agree with Hanamichi. I see a lot of good threads being closed because the mod/admin thought it might lead to a flame war. In fact, I've seen some good discussions which were forced to stop due to one tiny remark by some idiot. Preventative measures are one thing, but simply assuming a thread is going to go out of hand is premature and unwarranted. I think threads should only be closed when necessary, when all attempts to get the thread under control have failed.