I've observed that Unix itself was a social networking platform. Your Unix account was your identity across many services: email, finger, USENET, talk, etc. And it was distributed. And didn't rely on cruft like ActivityPub.

Totally! ident alongside IRC too. So many reinvented wheels. (Side note- I'm a little sad that https is the only protocol used for everything anymore).

Still is if you have an account on sdf.org.