Data Centers/World Locations Info from the LIVE Letter

[Alhanelem]

The current servers are being shut down.

When ARR comes out, we will still be on the same servers. "shut down" != destroyed.

When ARR comes out, and you log in to the game, your character will still be on a server called Gungnir, along with all the other people who also had characters on that server.

all NA linkshells will plan ahead and move to another server of their choice thats based in NA.

That's a bold assumption. I think most current players will stay on their current server. It's a lot easier than moving.

Just because you have the choice to play on one server does not mean you should do so if you want to enjoy the game.

You can enjoy the game on any server. It's up to you whether you want to move or not. I don't think most people will unless forced to.