On the 9th of December 1968, Doug Engelbart did a demo of NLS, his system for real-time interactive collaboration at a distance. This was also the first known use of a computer mouse. <https://www.techdirt.com/articles/20181207/15484041180/been-50-years-take-some-time-this-weekend-to-watch-doug-engelbarts-mother-all-demos.shtml>