There was some controversy surrounding Twitter's non-reaction to dealing with some allegedly harassing posts recently, with the noise being made by a user who is reasonably well known in certain tech circles. (The fact that she works for competitor Pownce I think is irrelevant, but some are making noise about it.)
Basically, Twitter is making a lot of stupid statements in public and not owning up to, well, what they own. They can do whatever the hell they want, but for some reason doing what's right is not high on their priority list.
I've been running community sites now for ten years. Our terms of service have been pretty straight forward, and we only boot people for various -ism's and hate, harassment and spamming. Contrary to a few noisy morons, we've never bounced anyone for having a dissenting opinion. We have bounced people for being illiterate morons or just being generally stupid in a way that doesn't contribute anything, and we do so because we can. It's not an issue of our TOS, it's an issue of doing what we think is best for our community.
So why is Twitter so reluctant to do anything? It's not because they don't want to get sued (because you're actually quite covered under various federal laws), it's because they don't want to appear unpopular. What a bunch of crap. Get some nuts and do what's right. I can tell you from experience that your community in the long run wants that.
I've criticized Twitter before, mostly for the fact that it's still a niche feature, not a business, and some people spend way too much time being connected. But regardless, I'm so tired of all these "Web 2.0" idiots trying to put high ideals over common sense (like revenue), especially when it involves problems that were solved in 1.0 by countless sites that came before them.