Mike Ferguson, a Systems Desginer for Guild Wars 2, published a developer’s blog with many community based question regarding WvW. There were a myriad of topics he discussed including siege engines, bonuses and more. The most interesting mechanic he discussed was Server Transfers:
Some of our more astute fans asked about the complications involved with switching servers and how it would interact with world bonuses. Every account has a home server where your characters are created. You can only fight for your home world in WvW. You can visit other servers, and while you are visiting, you still get the world bonus from your home world instead of the bonus for the world you are visiting. If you switch your home server, you lose the bonus from your previous home world and are not eligible for the bonus for your new server at least until the beginning of the next battle for the Mists. We may extend this disqualification into the next match or possibly even longer to discourage people from switching servers right before a battle ends in order to get an awesome bonus. You will have to pay a fee to change your home server (price undetermined), and that will also discourage people from server hopping to chase world bonuses.
Also, if you want to ask Mike Ferguson any questions, he’s hosting an AMA in several hours (9am PST) on Reddit.