Take the US, for example. When the iTunes Store first began selling music, it did so in a proprietary format that only iPods could play. If you had a Zune or Sony MP3 player, you were out of luck. Apple also prevented you from copying your files to more than five computers.
以美國為例，剛開始消費者在蘋果的 iTunes Store 網站上付費購買的音樂，只能在蘋果自己的 iPod 上聽，完全不能在微軟的 Zune 播放器或新力的 MP3 上播放；蘋果也控制音檔複製到其他電腦上的次數（限定 5 台）。