What is the difference between atx, extended atx, and micro atx in a computer case? what cases are they put in

atx is normal, extended atx will go in those monster cases and the micros are for those tiny little square boxes. the case name is atx case, extended atx case , ect. most of the one's you've seen are atx.. extended is for hardcore gamers and micro is just for people who want to shell out the $$ for a small, chic looking case..