IBM did a roadshow around 79-82 time frame in the UK and showed off plasma displays. They were very cool. Orange glow, very fast response they were built into the walls of an IBM mobile trailer hauled around the country drumming up business in the university towns. I didn't see one again until a very early Toshiba luggable in the early 90s.

PLATO seemed to me to kind of not lead anywhere solid. The field of computer aided instruction went on of course, NATO funded summer schools across Europe looking at it for decades. Maybe if you're in the field it has strong roots and a context. I worked alongside people in the space in that time and it felt like it wasn't living up to the promise.

That said, lots of things stem from it. All across the surface of things we do today. Mice, workstations, immersive experience, scripted interactions. I'm not sure I buy "email was born in PLATO"