Two billion songs have been sold on iTunes (as of Jan 9, 2007). Granted, many of the songs were on the radio at some point or familiar to music consumers. However, hundreds of millions of songs were purchased by people that only gave each song 30 seconds of consideration. These song buyers never looked at the band, never went to a show, and never listened to the album; they just bought the song – on the spot and without much thought. If you have ten minutes, read about “The Long Tail” in Wired Magazine