What is truly original in music or art?

This article is a sad, but interesting commentary on a tricky legal and artistic issue. What creative thoughts and ideas can be "owned"? And what exactly is required to call something "original"? ) It's very difficult to come with something so unusual as to be completely unique or original, but that doesn't mean we can't add something different and worthwhile. Art, by its very nature, takes us from the familiar or shared experience into the realm of new thoughts, ideas and emotions. But, in both music and visual art, where do we draw the line between referencing or playing with another's familiar idea and piracy or copyright violation?

http://www.techdirt.com/articles/20110624/01393814836/kind-blue-using-copyright-to-make-hobby-artist-pay-up.shtml