It was 1996. I wanted a hotmail address (pre-Microsoft). I wanted a cool, relatively short one with NO number in it. I scratched my head to think of something that no American would ever think of. So I thought - local dialect. Came up with neepheid - neep heid, lit. turnip/swede/rutabaga head ie. idiot, basically. In Scotland there is a long and rich tradition of playful, food based insults - neep, tattie, dumplin' - all synonyms for idiot/imbecile.
Anyhoo, neepheid was indeed not taken so I snagged it and it has been my nom de guerre ever since. Managed to keep it on most online platforms. I use neepheid_prime when I've been beaten to it.