I’ve always been busy with PKM. As I’m always doing a lot of things, help with a lot of volunteering and projects and study all over the place I really needed aids to track all that.
What if I have 15 minutes time to spare? What should I be working on?
It first really took of on my Psion 3c. Finally I started to be able to track events and people and many other things. Later I bought software as The Brain and tried and used many others since.
Picture from: Snowmanradio, from Wikipedia