The numbers announced by Apple today are staggering to even normally reserved analysts, who noted that after a somewhat slower summer buying rate, App Store downloads globally have exceeded more than 10 million a day in much of September.

After the App Store launched on July 11, 2008, it took nine months to hit 1 billion, and only six more months to hit 2 billion, noted Carl Howe, an analyst at Yankee Group Inc.

"The more devices that are out there, the more people want to download software, and they see it's an easy and fun experience," Howe said in an interview. It also helps that Apple has attracted 125,000 developers to its iPhone Developer Program, he noted.

After the in July, analysts were heralding application stores, including several imitators of the App Store, as the new way to buy software.

"You don't have to go to a store to a buy a disc and get the ultimate in instant gratification," Howe said.