Recently I received an email from the AdSense team about content on one of the user generated pages. It said I had 72 hours to remove it because it violated child safety rules otherwise AdSense would be disabled on that domain.
I removed it promptly and set up some more safe-guards in PHP and added some things to robots.txt. However, I think that's only moderating the problem.
How do I stop users from writing such content in the future?
Most of that stuff is meant as a joke, it's even posted in the humor section. However, I don't find it very funny and neither does Google. Users can already tell me whether or not a page is against the rules and I have filters set up in PHP to strip out profanity and other bad words. And if I ever see anything, I delete it, obviously.
Nonetheless, I can't think of any way to moderate phrases, especially ones which use a lot of slang words.