There seems to be a lot of rumors circling about this. I read about it on another news site a day or two ago.
What I find strange is that they're purchasing it for $2 billion dollars. This doesn't feel like a logical business move on Microsoft's part. Most people who want to buy Minecraft already have, with the exception of children who are just getting old enough to want it.Unless they intend of course, to somehow release a Minecraft 2 at some point, and monopolize that.
Anyway, I'm not believing anything that's based on rumors, especially when the rumors have come from out of nowhere. I've been with Minecraft since early Alpha, and I've followed the Mojang team through the whole journey. I can't imagine them selling out after all this. Although, I definitely would if I was them.