Social media is centered on users (you follow other people, not topics

This is the exact reason I never became interested in Mastodon. Following people just isn’t my style. The only social media I use is YouTube (without an account) because apparently Lemmy isn’t social media.

if forums are social media, or the internet more broadly is social media, would that include shit like, newspapers? And like, the library?

Great way to put it. That really is the root of it.