Delete a song from a playlist

Delete a song from a playlist: "When you remove a tune from the Library, iTunes doesn't always offer to delete the song's file from the hard disk. Here's why: iTunes has a default folder for the music it knows about. On the Mac, this folder is in your User directory at Music/iTunes/iTunes Music/, and on Windows, it's located inside My Documents at My Music\iTunes\iTunes Music\. Not every song file in iTunes needs to be in this default folder. Any song file can be added to the iTunes Library, no matter what folder it's in. If it's in the default folder, iTunes assumes it owns the file, so it offers to delete the file when you remove it from the Library. If the file is not in the folder, iTunes figures it belongs to somebody else, so it shows good manners by not deleting it."