Specifically, on messageboards.
I’m a pretty prolific poster on several different internet messageboards, and on every one of them, invariably someone says something that a moderator does not like, that the majority of the board doesn’t like, that is mind numbingly stupid/sexist/homophobic/racist/etc. The immediate reaction by the majority of the moderators is to either delete the offending post, edit the offending post, or ban the user.
While all of these methods are successful in curtailing the further abuses of the post or poster, they don’t do much to really prevent it from happening in the future. Posters can change IPs and come back, other people will post the same style of drivel in varying degrees of inflammatory nature, and then we’re back to editing, deleting or banning.
So how can a community deal with problem posters without resorting to outright censorship? Engaging in debates, constant disapproval of problem posts, eternal vigilance against the infractions imposed by the initial forming of the community. People in real life don’t staple people’s mouths shut when they talk shit, nor do they, normally, instantly resort to barring them entry into the premises.
People are more free to be assholes on the internet, because the threat of reprisal is so minute, and the reprisal itself ineffective. Communities that get behind their principals, rather than heavily moderating their forums, which brings stagnation to conversation when the normal posters have the fear of being banned controlling their actions, generally don't need the level of moderation that is seen on other boards. As with DRM, that threat only applies to legitimate users, the people who are the problem don’t care about the possible repercussions.
Replacing censorship by fostering a communal sense of what is and what is not allowed, and having community members all shout it keeps communities vibrant. The people who initially offended, now instead of simply restarting their router and creating a new sign in name, must justify their idiocy. Rather than screaming censorship when their moronic drivel gleans a reaction, they can now stand behind their words. Or stop with that entire train of thought, and abide by communal standards. Is that going to change their moronic opinions? Probably not, but it will at least make them stop annoying me with it.
Of course, in communities where there are only a few of the people willing to shout at the idiots, it’s usually the idiots that shout loudest and people calling them out either get drowned out, or give up. How to stop that trend is anybody’s guess. I certainly don’t have any meaningful input.