Wow, I understood jobs completely different from all of you I guess.

What I understood from the 2.0 PDF's and LIVE Letter was that once you got a class to level 30 you would do a quest to get the job stone associated to that class. (Ex: Archer Lv.30 Job quest unlocks Bard Job Stone) Then once you got the Bard job stone that would unlock another set of challenging quests which would reward you with new job abilities. So the way of "leveling" a job would be through a challenging quest chain.

Oh well, that's just what I understood, maybe I got it all wrong.