MajicMan: First, it is Kotaku as the source so I take it with a large grain of salt.
That kind of rumors don't get out of nothing. Even if it's not true that Microsoft will get Obsidian maybe there are serious plans inside the company to sell it to some big publisher.
MajicMan: Second, why would Obsidian agree to this when it was MS who almost put them under when MS pulled the plug on Stormlands?
This was years ago. Maybe they received a generous offer? Who knows... Alliances can change quickly.
MajicMan: Third, if it does happen, Obsidian will never get out a game before MS closes the studio. No company in the game space - not even EA - destroys more good/great studios and IP than MS.
The list:
Ensemble Studios (Age of Empires)
Obsidian (Stormlands)
Platinum Games (Scalebound)
Lionhead Studios (Fable)
Mistwalker (Blue Dragon)
Bungie and Epic Games couldn't deal with MS anymore they both left and walked away from mega IPs in Halo and Gears of War.
I wouldn't be that pessimistic, but everything is possible.
CMOT70: New Alpha Protocol on the way, built on the new Slipspace Engine.
This actually would be great, but I'm afraid Alpha Protocol is not a powerful enough IP for Microsoft.