Software from Apple that is widely used to organize media on the computer as well as iPods, iPhones and iPads. Introduced in 2001 for the Mac and 2003 for Windows, due to the sheer number of PCs, more people use iTunes on Windows than they do on Macs. Apple's iTunes Store is also integrated for purchasing media and software, and a user's existing media collection can be added to the iTunes library as well. Restrictions Apple copy protects TV shows and movies sold on the iTunes Store, and it previously protected its music. Therefore, there are certain restrictions. For more details, see FairPlay. Home Sharing When Home Sharing in iTunes is turned on, users can stream their content to their Apple TV boxes for home theater viewing. Playlists can also be opened to other iTunes users on the network, and titles can be streamed from one computer to another. Originally a "share-but-not-save" feature, in 2009, Home Sharing in iTunes 9 finally enabled users to copy files across the network, not just play them. See iPod, iTunes Match, iTunes U, media player and playlist.