This is what I got from my friend the moderator (and it used to be like that a few years ago when I was a mod): Any poster has the right to have their post removed (after they prove they are the poster) as ownership of posts remains with the poster (and not with the site) at all times.

If other posters replied between the request to remove the original post and the actual removal, their posts remain but factual references to the original post are removed.

I remember that a couple of years ago, a poster asked for his 10 years' worth of posts (around 10,000) to be removed and the site obliged.