Do u know about Pandora? I’m not talking about old myth, but an online radio @ pandora . You can hear your favorite musics here. So, how they know your favorite music? At first, they will ask you the artist you want to listen. After that, they will automatically play your music. For example: You wrote Michael Buble, and guess who they played? It was Sinatra. They prepare some playlist for you according to your input. There is a link that explain why they play that music. It said that this track features smooth vocals, a horn ensemble, acoustic piano, jazz-pop melody.
The engine of Pandora is music genome. I think music genome mine the information in every track and store it. If i wrote Michael Buble, music genome will search other track that have high similarity with Micahel Buble. So that the results are Sinatra and Barry Manilow. It sound like association Rules 😀