Many years ago, as an avid Knight Rider fan, I would use a handheld cassette recorder to record the audio portion of the show so I could hear it on road trips. Pretty bizarre, yes, but we didn’t have a VCR. I’d do the same when a popular new song came on the radio, waiting patiently to hit “record” and write the music to cassette tape. Over time, this turned into copying CDs, downloading music, burning CDs, uploading .wav files into iTunes, swapping hard drives. Only until recently, music was tied to the medium, but along the way, one impulse has not only persisted, but grown in strength: As social animals, we want to discover and share music, and external forces are working in concert to unbundle all types of media. These forces helped produce services like Grooveshark and Rdio , new incarnations of the Rhapsody subscription model, where users pay monthly fees to access catalogs and additional fees to carry that music with them. In parallel, services like Shazam and SoundHound help us identify music we hear, and Instant.fm , Last.fm , and 8tracks help us create new playlists and keep track of what we listen to over time.