Copyright issues are valid if they protect the artist. However, they mostly protect the large music companies. Youtube has been rattling so many sabers recently that account holders remove videos for fear of having them removed -- which also is increasingly happening. Three or four on my playlists (not uploaded by me) have been removed, and I am not even sure which they are. They are probably songs I have on CD, anyway, but as I like to share music with friends and don't know how to convert my iTunes to mp3 it is helpful to have them on YT.