Originally Posted by
omlech
Per account. The way servers will work in GW2 is different than what you're used to. All characters will be stored in a centralized database and your name is going to be 100% unique, no one else in the game will be able to have your name. What this means for gameplay is that you can hop servers for free at any time. So you'll be able to play with Server A with a group of thousands of people, then you could go to Server B and play with another entirely different group of thousands of people and so on. You can just hop servers at will, for free. So you can form friendships across any server you wish and play who you want to play with, no need to create a new character or anything. There's only one thing to be noted. In order to prevent people from jumping to the best WvWvW server every 2 weeks, when you move servers you'll be unable to take part in WvWvW for an unknown period of time. Right now we have no idea how long or if that's still the case.
One can ASSUME that if you go back to the server you came from you'd be able to do WvWvW, but that is just my own speculation based on the whole fact that their game design is about doing what you want, when you want.