ysabetwordsmith has written a very thoughtful essay on tags, warnings, and related issues. I confess I am not at all a thoughtful person, and I have almost no serious trigger responses (I do know how lucky I am in that regard), and I was simply charmed by the phrase "angst-ridden triggerfest of fractal doom". If you like good writing about writing, I encourage you to check out the post (and to comment on it, if you wish; as she says, "feedback is candy").