Massively: Will the jobs that are previewed going to be linked to specific classes, or will they be somewhat more flexible?
Naoki Yoshida: To answer that question, we're just  going to go into a little bit of an explanation of this job system.  Let's say you're looking to become a Paladin and unlock the job. What  we're planning is that you can get your Gladiator to level 30 and you  also get your Marauder to level 15 -- and please note that these numbers  are not set in stone. When both conditions have been met, you can  unlock a quest, which you can accept to unlock the Paladin job.
Once that class is unlocked, you will earn a job stone (again, not  necessarily the final name). When you equip that, you can change your  class into the Paladin job. Beyond the level 30 quest through which you  get the job stone, there will also be quests at, say, levels 35, 40, 45,  and 50 -- just as an example -- that deliver you the story of the  Paladin job.
The level of the jobs will always be connected with the base class, so  by earning experience as a Gladiator, you will make your Paladin  stronger, and any experience earned as a Paladin will go toward your  Gladiator experience. There's no necessity to go and raise your Paladin  separately from your Gladiator. However, there will be job-specific  weapons and armor, and to unlock these, you'll need to do the quests  after unlocking the jobs. Similarly, weaponskills and abilities won't be  earned through levels but by doing those quests. Experience is how you  improve your classes, but the quest chains are how you improve your  jobs.
Obviously, the question is what's different between a class and a job.  After discussing with the battle team how we wanted to do this, we  decided that for light parties and casual play, we wanted players using  the class system where you can freely mix and match abilities to make an  all-around type of character. Jobs we want to make more specialized,  like you see in a lot of other MMOs, such as where the Paladin would be  designed as a tank. They have special abilities to defend other party  members, and while attack power might be lower, they'll have abilities  that will enhance defense and allow them to play a certain role in their  party.
Of course, during this job system, to make sure that the job is  specialized, there won't be as much freedom in using abilities of other  classes. Players will be able to play a specific role, and with that  they'll be able to know their roles in high-end battles that require  more tactics and a more specific type of playstyle, rather than solo  battles, which are more open and where we'd rather have players be using  the class system to meet a more flexible style.
The best way of thinking about it is probably two different modes of  character fighting style depending on what type of content you'll be  playing.