Firstly, we need some definitions of how the word come to be.
Epic: Very imposing or impressive; surpassing the ordinary.
Ism: A belief (or system of beliefs) accepted as authoritative by some group or school
Epicalism is a word that means something is so epic that you believe it must be shared. Everything epic must be shared so it will be.
Woah! Dude!! THAT WAS EPIC! I'm going to post that to Epicalism so that everyone online can share in the epicness!