I don't think it's nearly that clearcut. Just to take an example, these days a lot of communities / interest groups are organized as Facebook Groups. Or subreddits. Is reddit social media? It has an algorithmic feed mainpage, it has profiles and likes and dms. You can make self-posts that are not posted to any subreddit just to your own profile. So if you think about it, it's actually very similar to facebook from a feature standpoint. But the culture is different. What about discord? I think it was originally meant for voice chat, but it also hosts communities / interest groups and quite a lot of other social network features. It does however not have a feed of posts, and you can't post things to your own profile. But you can set a status, which often is the precursor to a feed.