VisiCalc, the original spreadsheet, was first demo-ed to the personal computer press in a special room at the West Coast Computer Faire in San Francisco on 12 May 1979.
The spreadsheet is a computer application we now take for granted but being shown the idea for the first time came as a real eye opener. I wasn't among the press invited to "the launch" of VisiCalc but I did use a later version on the Apple II and found the idea of being able to change the contents of cells to do "What-If Analysis" revolutionary.
VisiCalc was the brainchild of Dan Bricklin who invented the spreadsheet grid that is now so familiar. The name, however, wasn't his idea - he had had "Calcu-Ledger" in mind for the product. It was instead the name coined by Bob Frankston, co-founder of Software Arts and the programmer who did the assembler coding on the project overnight when it was cheaper to use the time-sharing system, and Dan Flystra who agreed to distribute the product after both Apple and Atari had declined.
VisiCalc made the Apple and the IBM PC a success - people bought personal computer simply to run VisiCalc. At its peak it sold 2 million copies at $150 per copy in 12 months. But its success was marred by Software Art being slow with new releases and then by a lawsuit brought by VisiCorp, Flystra's rename distribution company.
By the time the messy legal wrangles were settled Lotus 1-2-3 had the market and Software Arts was almost worthless. Lotus acquired Software Art's products and other assets for next to nothing and in doing so avoided the `look-and-feel' lawsuit that Software Arts might have won against them in the following decade!
For more of this history see
Dan Bricklin - inventor of the spreadsheet