Since back-to-school season, Go-GURT has been running a digital music download promotion. Kids get codes and can download all kinds of tween faves: Demi Lovato, Miley Cyrus, Jonas Brothers, Jesse McCartney (all have been in the top 5) but "Hey there, Delilah" ranks number one, week after week. That's by a band from Lombard called the Plain White T's. It's not even new. What's your theory?