The short answer is not much.
Back when we first created the forums, I was used to how it was on other sites. I wanted a place that if people were unruly and just needed to fight it out, no holds barred, they could have the entire conversation moved there, and anyone who wanted to see it, could follow. I didn't want this forum to be draconian, and try to moderate out all disagreements, but I also didn't want fights that were using questionable language to be in the public area where we try to keep it family friendly.
It hasn't been needed. With very rare exceptions, everyone has been able to discuss different views with civility. The conversations might get heated, but for the most part, they've all been very well behaved.