Seriously, that many people haven't heard it being referred to as Blops yet?
Anyway, not surprised it outsold MW2. A lot of people I know avoided MW2 based on its lack of dedicated server support, or were introduced to online shooters via a friend's copy of MW2 - either way, they didn't buy it at launch.
Blops offered dedicated servers, had the entire MW2 fanbase, and the extras who'd decided to get in on the next big thing. And the proceeded to look awesome throughout its advertising campaign, turning some of the slightly less jaded cynics, such as myself, from a position of "don't care, it's just another CoD, won't get it" to "Ooh! It's like MW2, but not horrifically unbalanced! Ooh! Wager matches! Day one purchase!"
And you know what? I'm having fun with it. Maybe not as much fun as I had with Reach, and I'll probably move back soon. But still, fun. Sure, it's not perfect, nothing is, but it's ironed out many of the flaws of its predecessor, and is enjoyable to play.