If your 18 year old daughter posts pictures of her butthole that's her choice. My question was why is porn somehow worse than videos about video games or book reviews. What if your daughter makes videos about games while wearing skimpy clothes? What if her book reviews are about trashy lurid romance novels? Where's your line for prudishness? Individually you may not want your daughter doing it but if she chooses to, or more importantly someone else's daughter chooses to, who are you, I, or other random people to shame them for doing so? It's their buttholes (and bodies) and they can do what they like with them.