Most Virtual Worlds are for kids (6-8) and tweens (9-12). ourWorld is, for the most part, for teens (13+).
From a community standpoint, that provides a lot of challenges. Teens are notoriously difficult to please. The content teens want is basically juvenile adult content. They want to swear. They want to talk about sex. Some want to talk about booze and drugs and everything else any sane site admin would want to avoid entirely.
So, what do we do? We monitor. We have clear expectations. We remove the worst offenders. The most important thing I do is treat everyone with respect. I say "There are kids here, we don't know how old anyone is, and we can't have this sort of thing." Either they get it, and the problem is solved, or I shut them down, and the problem is solved. Some of the people I chat with most frequently are people I've sent Code of Conduct warnings to. Good kids (with dirty mouths, like that's something new!)
I'd say 90% of the kids on ourWorld are saying and reading things their parents wouldn't completely approve of. I'd say less than 5% are saying things that are really out of line. I review chat logs, but that doesn't give a good sense of the conversation, as it happens. I wander around the site using in an assortment of guises, making conversation or just reading. Most of the time, these teens are talking like teens, which is tough for a grown up like me (and their parents) to handle, but there is nothing wrong with it.
In the words of a generation older than even mine, The Kids are All Right.