Warning: This writeup is for Marvel readers and/or fanboys only. You have been warned.
Recently, the old Counter-Earth in disarmed42's writeup was replaced by another alternate Earth.
In the Heroes Reborn crossover, where Marvel tried to recreate several of its famous characters in order to boost sales, it was revealed that the original versions of these heroes had been transported to an alternate universe created by Franklin Richards, the son of Mr. Fantastic and the Invisible Woman. While the heroes eventually returned to the main Marvel Universe, Doctor Doom was left behind to conquer that world in the sudden superpower vacuum.
Due to circumstances too complicated to explain, this world, called 'Planet Doom' by its new ruler, has become Marvel's new Counter-Earth.