Well, I've heard world passes are worth the value of 6 characters because that is the max party size. It is supposed to allow players who have 5 friends who want to be in the same party (and take over the world, yada, yada) to be in the same server, but also remember if you sign up at the same time you should end up on the same server anyway, but if you don't just provide your world pass to a friend and they can 'jump' to your server (although they will probably suffer some kind of stats fall).

Hope that helps, if not I will be back, mwhahahahahahahaha, Baloki