The web has never responded very well to censorship. So much of the web is about freedom of expression that whenever someone tries to express himself, and is prevented from doing so, he feels disenfranchised. That applies even more so in the case of the Scunthorpe problem, because people who weren't trying to swear in the first place feel much more aggrieved.
On the other hand, website owners do not want their image damaged by users who can't keep their potty mouths shut.
When developing sites that allow users a voice, we need to find ways to protect the website owners, or the atmosphere of a community, without damaging the goodwill of the user base. Any website that depends on user input, and which doesn't have any users, is a failure.
Profanity filtering is not the answer because, at least, I've never seen it done well enough to be both comprehensive and unintrusive. All problems that relate to processing natural language are extremely complicated. We have barely started to scrape the surface in terms of parsing English text, let alone extracting the semantics from it that we would need to determine if a word is offensive. So any attempt at a naïve profanity filter is doomed to failure. For example, you can be profane without being offensive:
She turned round and screamed, "Fuck off, you stuck-up bitch". I was appalled!
You're a grumpy old bastard, but I love you.
and you can be offensive without being profane:
I did your mum last night. She's fatter than a blue whale, but she knows a trick or two. Your sister does too actually.
and let's not forget the cases where you can't tell:
Do you have a cock or do you just keep hens? Oh, we have a big gold cock. You know, the pussy is afraid of him!
Ok, the last example is contrived and of course nobody would type it with a straight face. Still, in the right context, it's innuendo not profanity.
With those insurmountable problems, there's simply no substitute for a human keeping an eye on things. However, even with moderation, there are problems to face. Exactly what is acceptable? Moderators can easily pronounce on clear-cut cases of abusiveness or offensiveness, but people have different sensibilities as to what's acceptable. It's also fairly easy for moderators to miss the odd bit of abuse, especially if it's only offensive in some contexts.
One trick to help keep control of the situation is to carefully set the tone. If you can use the language and style of the website to convey a sense of what might be appropriate, you can influence the tone users are likely to take. Though moderators still have to check the same amount of content, this reduces the chance that something untoward will slip through. Phrases like "Interglobal Inc do not take any responsibility for the content of this service" - phrases which are of dubious merit anyway - may have the opposite effect, by giving users the impressi0n that they don't care what the tone is. You also stand to lose control of the tone in the subconscious minds of users if you use some well-known software - phpBB for example - which users might have used elsewhere and come to associate with a certain mode of speech.
If you do censor people, a light touch is often better than a heavy hand.