I'll restate a third option here that I made in the censored thread (woohoo, I have read a thread Eliezer Yudkowsky doesn't want people to read, and that you, dear reader of this comment, probably can't!) Make an option while creating a post to have it be only viewable by people with certain karma or above, or so that after a week or so, it disappears from people without that karma. This is based on an idea 4chan uses, where it deletes all threads after they become inactive, to encourage people to discuss freely.

This would keep these threads from showing up when people Googled LessWrong. It could also let us discuss phyggishness without making LessWrong look bad on Google.