The first generation iPod shuffle was designed to be easily loaded with a selection of songs and to play them in random order. Owners of existing iPods had often left the music selection to “shuffle”, and the iPod shuffle was a way of implementing that in a much more cost-effective fashion. It relies on the use of an “autofill” feature in iTunes, which can select songs at random from a user’s music library (or from a specific playlist) and copy as many as will fit into iPod shuffle’s memory.