They both involve a way for people to vent aggression in a pacifist kind of way, Instead of shooting someone, you can rap it about being violent or vent it in a game.
Dr Major added a third outcome was the possibility that lava would work its way up the volcanic vent and "ooze another lava pancake on to the dome, increasing the dome size".
Many existing Pro users, thinking they would be forced one way or another, took to social media and Flickr forums to vent their frustrations at the potential loss of that limitless space.