Originally Posted by Ragnaris 
I don't know Oblivion's overall sales, I suppose I'd have to look at the numbers somewhere, but I'm sure Skyrim will outsell it very soon if 3.4m is accurate.
Of course it will. Sequels almost always outsell the the previous game, especially in a series like TES where there's 5-6 years between titles. They're selling to a larger base of gamers for the most part.
The only time a sequel doesn't outsell the previous game is if a developer really screws up… like Dragon Age 2.
