I'm always glad to see PLATO getting its due. We had a PLATO terminal in our house - beautiful wood frame with an orange plasma screen, hardwired in to the University of Illinois mainframe at 1200baud. Besides remembering playing a lot of Empire with the college kids, there was also a cyber-nanny called "The Enforcer" which admins could place on "educational" accounts to limit access to games at certain hours of the day (or if games were taking up too many resourced on the mainframe.) My Dad used The Enforcer as a very effective incentive to get my homework done.
I'm glad I didn't know these games existed , I might have not been studying. Plato terminals where great for freshman chemistry. example exams and problem sets were available in the almost always empty room in the tower library.. it's time in the early 90s before the web made info uniquitos, I really appreciated the quizzes and the explanations of the answers it gave..
You might also be interested in the book "Dungeons and Desktops". The guy who wrote it does really great videos as well. Do a search for "matt chat wizardry" to see interviews with Robert Woodhead et al.
I remember PLATO (PLATO Notes, specifically) as one of the inspirations behind Lotus Notes. It's quite interesting to see how seminal the ideas behind it were -- given the right commercial decisions, Notes could have pre-empted the web.