I like how you can't delete certain comments, it requires you to think out your response and such but I think there should be a feature where you can delete comments on your own page, or at least ban comments on your own page.
I really like this idea; sometimes I would look back at comments I made years ago, and just bang my head on the desk at how immature and stupid they are. And yes, like you mentioned in one of your replies, it does get pretty cluttered if you decide to hide a bunch of comments.