Not every artist has a signature song. Someone like The Beatles, Madonna and MJ don't really have a specific signature song because a lot of their discography is full of iconic, well-remembered classic hits. Likewise, there are a lot of recent artists who don't have that one hit yet that sticks and will go down as their signature song. For example, One Direction don't have one even though WMYB is probably their biggest hit.You don't see their name and instantly think of that song.
