Part of my point is that even engagement might not be the best metric. For example, here in hn, I'm far happier if people don't post than if they post something

Part of my point is that even engagement might not be the best metric. For example, here in hn, I'm far happier if people don't post than if they post something trivial or uninteresting (your post and comments are interesting as I think this is a discussion worth having).