Excerpt:
Way back in the 1980s, I worked on what was then a new kind of software called outliners.
They started out as simple hierarchy editors, used by lawyers, educators, students, engineers, executives; people who think -- to plan, organize and present their ideas.
Over time the products became more full-featured, especially on the Macintosh. Then the category died out, no one can explain fully why that happened, but in the early days of personal computers, outliners such as ThinkTank, Ready and MORE were popular programs.