iTunes is a software application developed by Apple Computers to play digital music. On April 28, 2003, the iTunes application came bundled with a music store that allowed customers to download individual music tracks from their favorite artists. At launch, the iTunes Music Store offered 200,000 titles.
Before iTunes, the majority of music downloads came through file-sharing programs that were largely deemed to be violations of U.S. and international copyright laws. iTunes not only became the first digital music service to become financially successful, it became the #1 music retailer in the United States.
iTunes is not without its detractors, though. In order to sell music digitally, most of the files are encoded with Digital Rights Management (DRM) software to prevent copyright infringement. Apple's brand of Digital Rights Management encoding has remained proprietary to Apple, preventing music bought from iTunes from working on many portable music device other than Apple's own iPod.