Today in 1979, the first production copy (version 1.37) of VisiCalc was shipped. Wikipedia: “Conceived by Dan Bricklin, refined by Bob Frankston, developed by their company Software Arts, and distributed by Personal Software in 1979 (later named VisiCorp) for the Apple II computer, it propelled the Apple from being a hobbyist’s toy to a useful tool for business.” And: “VisiCalc went on to become the first “killer app“, an application that was so compelling, people would buy a particular computer just to use it.” Bob Metcalfe on Steve Jobs: “Then there was the time Steve invited me down to Cupertino to show me VisiCalc running on the Apple II–you know, the spreadsheet before Lotus 1-2-3, which was the spreadsheet before Excel. Steve was telling me that this would be the killer app for his PC. Having never seen a paper spreadsheet before, after escaping Steve’s reality distortion field that day, I didn’t get it. This didn’t slow Steve down. Sometime later, when the VCs (venture capitalists) asked me for a five-year projection of 3Com revenues getting to $50M, then I bought an Apple II as my VisiCalc machine. Steve then introduced me to his investors.”

VisiCalc sold over 700,000 copies in six years. While it was the first electronic spreadsheet for personal computers, Bricklin and Frankston did not seek a patent for it, and more sophisticated clones were soon released, including SuperCalc (1980), Microsoft’s MultiPlan (1982), Lotus 1-2-3 (1983), and Microsoft’s Excel (for the Macintosh in 1985 and for Windows 2.0 in 1987).