For me, the distinction isn't "Child Friendly", it's "Polite Company".
This board isn't where I go to slam a few beers, hang with the guys, and not care so much about being crass*. Instead it's where I come to converse with a mix of people from many corners of the globe, all of whom have an above average intelligence.
While I'm not offended by an occasional profanity, it is rare when I read the usage of one that I feel no other expression could've conveyed the posters intent. That is to say, more often than not, the usage of such terms feels highly unnecessary. As such, and as such terms very well could offend others, I think it's only polite to avoid using them except under the circumstances in which no other expression would suffice.
That is, at least, the rule that I myself follow, and I feel that most others here do as well.
Quite simply, to sum up:
So far I have moderated the forum with a "don't be a jerk" policy...
* - Slamming a few beers and being crass may occasionally happen in the f.DS.Forum Games community, as I treat those that play there as close friends, and fully expect them to tell me to shut-up if need be.