DMD is an abandoned coin. You can't mine it right now, when you try it doesnt give you anything. You get a lot of block finds, but no actual coins.
I think someone did a 51% attack on it or something. Anyways, its so valuable right now because no one can mine it.
Edit: Ahh, it was a victim of a 51% attack according to the developers. They need some help releasing a new wallet because of the fork.