ReDigi runs a digital music resale business. Buyers of tracks from iTunes or ReDigi can sell them using ReDigi’s service. The service scans hard drives of users and transmits copies of tracks to its cloud. Buyers wanting the music can acquire copies at a discount from iTune’s price from ReDigi. ReDigi was sued for copyright infringement. The novel question was whether a digital music file, lawfully made and purchased, may be resold by its owner through ReDigi under the first sale doctrine.