I used to post on FFN myself, and when my fiction went past the point of heavy innuendo, I came here to publish it. Obviously, I like it here, and although I did pull my work from FFN a while back voluntarily, that was for other reasons not related to content ratings.
But I did read the ToS, and I did agonize over whether or not my innuendo crossed the line. I have teenagers of my own, and I decided that if I wasn't comfortable with them reading what I wrote, then it didn't belong on FFN. Part of being a writer is being able to actually read the rules.