Apple has quietly removed the “Back Up to Disc” feature in iTunes 10.4, as indicated in a recently updated Apple Support article. First introduced in iTunes 7, the Back Up to Disc feature allowed users to backup all or a portion of their iTunes library to optical media such as CD or DVD, preserving library metadata such as playlists, play counts, and ratings in the process. This feature is no longer available in iTunes 10.4, with Apple…