I've got no confidence in this whatsoever. Anything with a tagline of "Imagine what we can make in 1000 years; we're gonna make it now" is pretty sketchy, they don't seem to have any credentials at all, and they're asking us to believe they can make the most ambitious game ever. If they're not delivering more than Dwarf Fortress, they're lying, and if they are attempting to do that, I seriously doubt they can. At best, I expect an incredibly watered down mmo "game" where they release expansions based on "tech points" that players pool together to create, and even then I seriously doubt it would work.

Also, Minecraft's world is, if I recall correctly, already larger than Earth is.