Word on the streets is that it is Blizz, and they are the only ones who leak information.
It wasn't to long ago that they said, "We are NOT going to make an SC2." One year later..... oh right SC2 yea..
However I have been hearing this too, but I'm not sure how well D3 is going to hold up to newer RPG's. Or how they are going to differentialize it from WoW. This opinion aside, I'm still getting it