A funny thing; the Ars Technica front page sorta feels like social media—they don’t quite algorithmically rank the comments, but they do hide very downvoted comments (as a sort of community moderation feature), and sometimes the author of an article will highlight your comment (making it visible on the article page). I would call it exactly the dividing line between social media and not social media, to the point where I’m not sure which side it falls on.
Meanwhile their forum feels more like an old school PhpBB thing. Actually I think it was PhpBB at one point, until a recent redesign.
Now their front page comment section and their forum have exactly the same back-end. (Like if you leave a comment on their front page, it also goes into a thread in their forum). Largely overlapping community. But, the vibe in the two different areas is completely different.