In 1979, Dan Bricklin and Bob Frankston created VisiCalc the world's first spreadsheet software. VisiCalc was an immediate success, became the Apple II's "killer app" and was credited by Steve Jobs with propelling the first explosion in personal computing. Ted Nelson, an internet pioneer, described the paradigm shift that the spreadsheet interface created, Five years later, in a high school on the other side of the world, VisiCalc was the first computer program I ever used.