Here is one way of measuring it:
In the last seven years. Over 9.9 billion songs have been downloaded from Apple Store via iTunes.
The company is on the brink of selling the 10 billionth song anytime before the end of February and is offering the 10 billionth downloader of an iTunes song a $10,000 iTunes Gift Card.
[Eligibility for participation are: 1) at least 13 years old and a resident of a country where the iTunes Store legitimately operates 2) One has to buy the music 3) Can buy music only 25 times a day 4) If don’t want to buy have to fill this form to participate]
The pace at which Apple made the iTunes music popular can be judged by these numbers:
5 billionth download was achieved in June 2008.
The pace at which Apple made the iTunes music popular can be judged by these numbers:
5 billionth download was achieved in June 2008.
1 billionth download happened in February 2006.
So while it too apple 3 years to reach the 1 billionth milestone. It took only 2 years to add 4 billion to the tally. Finally it took only 1 and a half year to add another 5 billion.