Dslam,
What I mean is that say I am the person being ignored and I post a reply to a thread. I would see it only. Now everyone else would not be able to see that post in theory. Now what I am saying is all I would have to do is log out to see the post dissapear. Then like most people they come back and register again. It would take some good amount of code to do this and then it really is not a deterant as I think the people would only register more names. I have seen this many times when you ban someone. There is no full proof way to ignore people as they always find a way to come back and haunt you. You could ban entire IP ranges to block them but then risk making other users mad.