How was poster identity handled in Usenet/NNTP? From what I remember, it was just a "From:" header and spoofing was easy. Or was there more to it? (Maybe because most posters wrote to their local server which require auth, you could see which server the message originated from and decide if the sender's address matched the server address...? It's been so long.)

If not, then Twitter, Mastodon, etc. all seem to have a somewhat strong notion of identity.