By inference, I can only think of, "Make Shit, Prove Worth".
On the topic of leveling, it's simply a game mechanism (as you mentioned with WoW)...it's part of what makes games fun. Of course, learning any skill is continuous--even playing video games, but the introduction of levels is simply to give tangible, albeit artificial, goals. It makes the gamer/user/learner feel good that they achieved another level. There are other gaming mechanisms employed in web applications, such as collections. Pokemon comes to mind. This is also pretty apparent in Friendster and MySpace.
I'm not sure that there's exactly anything wrong with employing game mechanisms to make something previously tedious a bit more fun for humans, but I can see how having "the wrong metrics to measure level" would encourage people to optimize on the wrong things (climbing ladders), instead of actually focused on getting better at the game/their careers/their job.