Edit: yes 1 to many communications existed but they either required expensive publishing or they were tied to a physical location (eg a physical notice board). Internet forums are globally available for anyone who is interested to read or publish and that turns out to be phenomenally powerful but in a way that pre-internet people could not have conceived of
https://americanliterature.com/author/mark-twain/short-story...
“So, unless aware of this dynamic, we shall at once move into a phase of panic terrors, exactly befitting a small world of tribal drums, total interdependence, and superimposed co-existence.… Terror is the normal state of any oral society, for in it everything affects everything all the time.…”
It was Innis who'd first drawn the connection between medium and tenor / characteristics of communication. See especially Empire and Communications and The Bias of Communication.
This is naive of me -I had never considered that there were physical message boards with replies being tacked onto the original message.