[oblio]

And what are "forums" and "bulletin boards"?

They're online environments (aka media) for discussions (aka a form of social interactions).

"Social media" is just the mass market name for forums.

Edit:

I'm kind of flattered that someone created a new account just to nitpick a comment of mine :-))

Keep on keeping on, senormenor: https://xkcd.com/386/