On the download end of things, Apple reported that they've distributed 14 billion App Store downloads, and 130 million downloads from the iBookstore. Those figures do include free apps, but that doesn't make it any less impressive. Developers have been paid $2.5 billion thus far.
iTunes, which obviously had a head start, has sold 15 billion songs. We suppose Apple should be thanking us, but we're grateful for something else: We're grateful that they chose to present these in the number of apps, devices, songs, etc. Because if we heard the cash value that we've paid to Apple over the years, it might make us nauseous.
source: Boy Genius Report