just found this thread.

XanBcoo is "mock ghetto" for my real nickname: Xan (from Alexander)
I wanted something narcissistic, like, "Xan is God" or "Xan is cool", and because me and my friends used to make fun of ghetto-slang a lot, I chose Xan be coo' and shortened it to:
XanBcoo' <-- when I joined GotWoot I forgot to capitalize the X and B and dropped the apostrophe.

EDIT: And have since had the X and B capitalized. But still no apostrophe.