I'v gotten pretty good at ignoring the idiots on forums. When I get insulted, I just consider the source and shrug it off. Once in a while, I'd like to click a button to shut someone out. But, since the majority here don't want it, I'll live with it.
At Fractalus, we do have it and it's set up, so that you can "unignore" the person your ignoring. I had someone there that I was ignoring, but, when I wanted to see what they were saying on a certain subject, I would just unignore them. That is if I was in the mood to listen or they actually had something worth listening to.