In 2001, some of the top songs included Fallin’ by Alicia Keys, Ms. Jackson by Outkast and Nelly’s Ride Wit Me. When people wanted to listen to those songs and they weren’t near a car stereo or their audio equipment at home, most carried music with them on skip-prone portable CD players, boomboxes or maybe even a homemade mix cassette.

Sure, some early adopters were already carrying a small collection of songs on a portable MP3 player (MP3s: the new-new thing!) like the Diamond Rio or Creative’s Nomad Jukebox. But these weren’t common, and you didn’t see them that often; there was no ubiquitous sign yet that, musically, the times were changing.

Enter Apple with its original iPod , a small hard drive encased in smooth white plastic that could stash between 1,000 and 2,000 songs, a sum that seemed godly at the time. Who would ever need to listen to 1,000 songs (or have access to that many) at their fingertips?…