I have been planning to do a post on Visicalc pretty much since I started blogging.
I have mentioned it in a couple of posts before, including one on the "Most Influential Software Programs".
In my opinion Visicalc was the most innovative software program of all time. It did not reproduce anything (although there may be some similarities to old ledgers). It did not build upon anything (as most software does). It was simply invented.
And then it was copied: 1-2-3, SuperPlan, Quattro, Multiplan, Excel, and others. And of these Excel is still in incredibly wide use today.
I have huge admiration for the accomplishment of Dan Bricklin and Bob Frankston. In all of the years since they invented Visicalc in 1979, nobody has created anything in software which (IMHO) has that level of creativity and innovation. Truly remarkable.
The reason I mention it today is that I came across this video on the two guys and their achievement.