The popularity of the App Store simply cannot be overstated. Last Friday, Apple approved their most ever apps in one day. 1394 of em. Over 300 were games.
That's like if the entire Blackberry App World catalog were published in just one day. 1400 is more than double the number of games currently on the PS3 (557) and just a tad short of the number of titles in the PS2's library (somewhere around 1,900).
In short, it's a lot of freaking software in terms of pretty much any platform...and it all came to the iPhone in just one day.