For more PLATO talk, the author posted often around these parts about the Friendly Orange Glow (
http://www.friendlyorangeglow.com/) (not to be confused with HN, the Friendly Orange Site...) and PLATO history (
http://platohistory.org/)
Also an Arstechnica thread from 2023:
PLATO: An educational computer system from the 60s shaped the future
https://news.ycombinator.com/item?id=35208286