@clive I have proposed something different -- ActivityPub recognizes different "content types" -- video, audio, Note (which is what you're reading now). One of the types is Article (typically full html documents). My proposal was that Article posts could be quoted but Notes could not. On the understanding that an article is something meant to be commented on publicly and not just semi-public correspondence. So you could dunk on a newspaper article but not a personal post, basically :)