ABSTRACT
When music formats get smaller, they fit into more places inside and out of the home. The CD, with a diameter seven inches smaller than the LP, and the diminutive cassette tape, catalyzed music portability. MP3 and other digital music files, freed from their reliance on a disk of any size, have no physicality at all and are therefore infinitely portable. Of course, you still need some kind of physical device to listen to virtual music files, but that device can be as small as a wristwatch or a slightly fattened credit card.
