The main purposes of a music video are to promote the song and artist in order to sell music and merchandise. A successful music video leaves viewers remembering the song and wanting to listen to it again. While music videos can serve different purposes like telling a story or showcasing an artist's talents, their overall goal is promotion. Michael Jackson's "Thriller" video is considered the most successful, selling over 9 million copies. There are three main types of music videos: performance-based, narrative-based, and concept-based.