I've enjoyed playing WoW for several years and during that time I've seen things like people typing the word Anal and then linking a character skill, such as the warrior ability Rampage. I've seen this go in in /2 trade chat, which is visible in all cities, for as long as it is 'funny', which can be about 30 minutes. No moderation is done and to get someone in trouble you have to open a ticket and complain. This went on across many different servers and lasted for months before I heard of anyone getting banned for it. Profanity is tossed around rather frequently as well.
In other words, it is basically just like the real world, which it is basically futile to try to protect kids from. My concern is simply for parents who are naive about what their kid is getting into. I personally don't see a huge problem with this. I was a latch key kid, found my dad's stash of Hustler mags at an early age, and I'm a normal adult with a young family etc. I rode my bicycle all over town, bought cigarettes from a machine, yada yada yada.
I remember in college I learned to prey upon girls who had been aggressively sheltered all their lives. Once they got to college they were just looking for a guy to go crazy with. I was determined to be that guy for as many beautiful young women as I could find. So really, as a parent, ask yourself, is it really the best thing to own a helicopter?