Followership is a strange word and I would go into all of the aspects of what good followership is, but I don't need to. Dick Cheney is the example of great followership. And, no, followership doesn't have anything to do with being a "yes man".
The idea of followership really goes right back to Ronald Reagan, who said:
"There’s nothing you can’t achieve as long as you don’t care who gets credit."
Dick Cheney is a living example of that axiom.
Good point regarding being a follower. I don't know if it's legend or not, but I remember a story about someone who once asked the mother of George Washington how she taught him to be a leader. Supposedely she said, "I taught him to FOLLOW."