Noob = someone new + someone retarded.
n00bzeros, not o's] = someone new + someone retarded + someone trying to be 1337.
nub = someone old + someone retarded + someone trying to be 1337.
And of course, the tard...but that one is self explanitory.
Noob = "Sup guyz do you have Naruto so I can download kthx! Oh wait, this is a forum chat nvm okbye!!!1"
n00b = "I|\/| S0 L33T AR3NT 1!"
nub = "LOL REMEMBER ME? I used the nick DarkAngel666 but now I am older so ya !!!11!"