I think one place HN falls short of what I think of as social media is that there's no following of individual accounts, that creation of networks and personalized feeds feels like part of the core of what separates social media from simpler forums. Reddit was closer to just forums as well but subreddits allowed you to more directly curate and associate between groups, now every user basically has their own little subreddit they can post on and people can follow and join.

Yes, so that's why I somewhat included it. But, it's definitely on the lighter side of social I think.

On HN, it's a lot tougher to follow specific people, though it's cool to see posts and then follow up with what they've recently posted or commented.