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I remember watching this demo a few years and being fairly impressed, but I was left with a kind of 'what is all the fuss about?' kind of feeling. It wasn't until later that I became aware of just how primitive computer technology was back in the late 60s.
The word 'visionary' is oft overused these days, but I think Englebart was a visionary in the true sense of the word. But he was more than a pontificating academic. He was engineering and building these systems with his assistants and students. He was looking at least 20 years into the future (we got the first rudimentart GUIs in the early 80s, I guess you could argue) and was building them in 1968.
One wonders what impact he had, both directly and indirectly on the state of the art of computing in modern times.