I think it's interesting that just about all other types of media (movies, TV, music, comic books) all have Content Advisory labels on them. Not for censorship purposes, but simply to inform a prospective reader/view on what the work may contain, so that they can decide for themselves if its' something that would potentially turn them off, or if it's something that, in fact, does interest them.
Since books dont' have that type of label...I've actually taken to inserting my own. [promotion removed - moderator]
Content Advisory: This book is intended for mature audiences and contains graphic violence, explicit sexual activity and disturbing imagery
I don't believe in censorship, but I do believe in giving people the right tools to make an informed decision about what they buy or read or watch. As much as i would love to sell a billion copies of my book...I'd rather have the right reader find the right kind of book for them. And I think a simple content advisory is a step in the right direction.
But that's just me.