What drove this success? Like you don't know, but: Call of Duty. Modern Warfare 3 was the best-selling game in terms of dollars, and Black Ops was #5. Skylanders also contributed, as it was the #8 best-selling game in the fourth quarter, and best-selling kids' game of 2011.
Digital revenue broke records again, with over 34 percent of that $4.76 billion net coming from "digital channels." No, you aren't forgetting some breakout XBLA hit from Activision -- those digital channels are COD map packs and WoW.