If you're not familiar with it, The Demo included demonstrations of "hypertext, object addressing and dynamic file linking, as well as shared-screen collaboration involving two persons at different sites communicating over a network with audio and video interface."
And the best part… The Demo took place on December 9, 1968.
Stanford University has an excellent series of annotated clips: here.
Truly a man ahead of his time, Engelbart's vision was to ask:
"How do we collectively use technology to map our future with integrity mindful of the perspectives of others and future generations?"