So That’s 100,000 Copies of Twitter and 900,000 Copies of Angry Birds?

Apple’s Mac App Store is off to an impressive start. It racked up one million downloads in its first 24 hours of business (the top selling app: Angry Birds).That’s a strong showing by any measure–particularly for a brand-new service with limited offerings that relies on an OS update for activation. That said, it’s not nearly as strong as the one put on by the iTunes App Store, its best reference point. That service racked up 10 million downloads its first weekend.