I don't use it as my alias--but my e-mail starts with "biggbill". That's a reference to an act done by a comedian named John Pinette back in the early '90s. John is very large, and said that he loved to go to buffets, as he was always assured of coming out ahead. He'd go into a Chinese buffet, and the owner would come out, frown at him, and say (in a decent comedic Chinese accent impersonation), "You too big! You go now! You eat veg-ta-bow. Veg-ta-bow good for you!" He also liked casino buffets--he'd lose money at the blackjack table, but more than make up for it at the steak table in the buffet. "Hit me again!...Hit me again!...I don't think the house is going to win THIS hand!"
From that act, a couple guys I used to eat lunch with from time to time (often at buffets) started calling me "U2 Bigg"--sort of a rock/rap reference to Pinette's line. And that eventually morphed into "BiggBill"--especially when "BigBill" was already in use when I signed up for the e-mail account.