A general observation about online comments: when I read an article online and want to know what other people are saying about it, I have no easy & simple way to do so. If your blog has a comments section, that's great, but what about all the other platforms that people discuss things on? (Twitter and Reddit [and of course HN!] come to mind.) I would love to see a comments system that provided insight into commentary…
Because the web has devolved into a bunch of walled gardens that try to sell their user bases to advertisers.
Nothing has devolved except the willingness of users to explore to find new content. But that's not because it no longer exists, but because for the most part new content is delivered to them.