Right, when this happens, there will actually be two servers on the internet with the full setup for hypnos.com and during the transition, some people will see the old one and some people will see the new one, and then gradually all the DNS records will be updated and everyone will see the new one. Only at that point will the old one be shut down, but doing it this way, there is little risk that the site will be totally unavailable for any period of time, and we won't lose any orders.
I might need to shut down the Forum at some set time, and move it all the way over to the new server, and disable the old one, so we don't have a time when there are two separate Forums receiving separate posts, no longer in sync. But with the Hypnos store and the rest of the web site, it won't actually hurt anything if there are two separate version for a few hours. We'll just make sure that all orders placed at both sites, are recorded and processed.