I've recently been enjoying YouTube videos by pianist, Robert Estrin. Estrin has created a large menu of videos under his brand "Living Pianos." You can learn about piano types, learn piano skills, and many, many other things. I highly recommend checking the videos out. Robert is son of Morton Estrin, a highly respected piano teacher and concert pianist. This video is just one from one of Robert's vast library, and in it he tackles the question, "What Makes Great Music 'Great'"?