Donald Bitzer, plasma screen co-inventor and the father of PLATO computer system, considered a precursor to messaging apps and more, died on December 10 at 90 (Harrison Smith/Washington Post)

Harrison Smith / Washington Post:
Donald Bitzer, plasma screen co-inventor and the father of PLATO computer system, considered a precursor to messaging apps and more, died on December 10 at 90  —  He helped shape cyberculture as the father of PLATO, a computer-based educational network that sparked the development of plasma screens and digital messaging.