P.S. I would propose that fac586 is not any more informative than my system generated forum name.
Perhaps not, but it is at least recognisable and—most importantly—easily distinguishable from user10370448, and user10734480.
And unlike many, there's a little further information my profile...
I'm not sure pop-culture references count as uninformative.
Would you say the same for these two?
esoteric maybe, distinctly recognisable - definitely.
Allowable passwords - nope