My mind is reeling with some of the possibilities suggested by the concept that Notch has described so far. The idea that you have an emulated computer to control your ship that runs even when you aren't playing is rather interesting. I imagine that with some degree of skill, the whole thing becomes a programming metagame where you're merely writing code for the computer to control your ship while you aren't logged in. (Would give you the advantage of effectively playing the game 24/7?)
I also imagine that there are simple ways to share computer code with others in the game so that you can grab and remix cool routines written by others. Perhaps someone crazy enough to build an ALU in Minecraft would write a BASIC compiler for the in-game DCPU bringing down the barrier to entry for everyone else. Carry that line of thought to a logical extreme: You end up joining 0x10c as a new player many years from now and your first steps in getting off the ground are to go download the DCPU port of the GCC, compile yourself the latest version of the community written kernel, etc.