AFAIK, there's dedicated servers out there - you can password-protect them and only give the password to your buddies - where you can upload your worlds (read: gamesaves) so everyone can play. So I guess if you transfer the right gamesave all your stuff and buildings and so on should be there? Not sure, though, only been doing this, so far, with completely fresh worlds to start over right from the start. Anyone can confirm this works?