Interesting interview with the co-inventor of the spreadsheet.
He argues that the plasticity of the spreadsheet made it 'hard to knock off'. I don't agree - I think the spreadsheet is incredibly easy to knock off. The plasticity is what makes a spreadsheet so incredibly useful - it can almost be seen as a different kind of interface to universal computing functions on one level. He also talks about how his background in computer science and as an MBA made this innovation a natural extension of his own skills and interests.