Like most stories, the origin is very simple…
Back in the eighties I ran a BBS called “The Qutron Executive” and also messaged prolifically on Keith Barnes famous five line BBS called “Mission Impossible”, sometimes Miss Imp, or Mish for short. For those who remembered those days, both boards were run with Wildcat BBS software.
As my name is Andrew, I used to sign my messages &Roo (and-roo) for short. Many members developed the habit of refering to me as Ampers and thus the nickname was born.
As I said, the story is a simple one 🙂
PS As a short aside, it was around 1986 that we adopted Internet messaging. Most of us, when we saw the huge long headers, came to the conclusion that this would never take off. So we all joined the ranks of the CEO of IBM who once stated there would never be the need for more than five computers in the world!