From someone with a bit of experience in online communities, I can honestly say that I think CBS' rules of engagement are the absolute bee's knees, far better and clearer than anything we see on LJ, or on pretty much any of the other supposedly enlightened, egalitarian blogging / online community sites.
(You don't need to be a lawyer to read it, for one...)
So, how do you break such clear, simple, enlightened rules designed to create respectful, thoughtful conversations? Easy. You expose them to the general public, and empower racist idiots to say whatever they want.
(And when you simply do not have the time to screen out all the racist hatemongers, you turn all comments off.)
So, if you have so many messages on your forums that centralized moderation isn't a possibility, what's the solution? Arguably, it's decentralized moderation. This, of course, requires empowering some of the community that develops around a site, as well as making sure that those policing it buy in to the culture of the site, but I don't think this is undoable.
You know, I think Barack Obama could potentially be the best thing that happened to this country in a long, long time. So good, in fact, that the people of our country would find a way to either have sex with it, put bullets through it, or reject it by uncomfortably large margins.
(Don't mind me. I'll be hiding over here grieving for our nation, thanks.)