One thing common among flat earthers is they are believers in all the most popular conspiracies involving secret societies controlling us all. Most of their recruits come from one of these conspiracy groups, like the illuminati, freemasons, secret base on the dark side of the moon, and others.
Also their believe in a flat earth is more than just the shape of the planet- much more. Many believe the Flat Earth is covered by a dome that displays an artificial sky including clouds, stars and planets all created to fool us. OTHERS believe the Flat Earth is the center of the universe and the stars and the sun revolve around us, Crazy stuff