History of Collaborative Editing
Martin Pittenauer (via John Gruber):
Martin [Ott] did research into if that was actually possible and found - beside other research - Xerox Parc’s Jupiter paper. I remember that we were all amazed by the simplicity and elegance of the approach. From that we started work in early 2003, finishing 1.0 of Hydra (now called SubEthaEdit) just 8 weeks later, eventually winning the ADA later that year.
