(away from this website)

People who are really into board games (Settlers of Catan/Magical Gathering etc)
People who like American Football who are not from the US
People who either like or hate or even know of Buzzfeed

There are more categories that I can't think of. Please add your own.

This thread isn't designed to deride these sad fools, just to catalogue subsets of humanity that in your experience only exist on this website.