Well, the name "Hikari" was already taken long before I joined, but it stuck as a nickname for me. I improvised by adding the numbers in, because it was my original username when I used to be on Bulbagarden, and if you notice my birthdate, I was born in October, which is surprise, the tenth month in your average calendar year! And given I was born on the 1st, it was fitting a 1 had to be in there, as part of the 10.
Yeah, interesting story eh?