I guess it would be possible, I think it\'s how IRC works (not sure lol, I read something about it a while ago). But I don\'t think it would be easy to use in a MMORPG.
What would be possible is to split the game into different areas, each one on a different server (okay, that would be stupid because it would lag when everyone is in the same area...)
Anyway, it is obviously too soon to have several servers, as they said in the news. But Having several servers also have its advantages :
-You can have slightly different rules : for exemple one server can be more focused on roleplay, another would allow PK, while a third one would be a special newbie server.
-It can reduce lag for european or eastern gamers, because no matter how many servers you around the world, if the main one is in the US, Europeans can\'t get less than 300 ms ping (more around 500 actually).
-they won\'t require any work : if you want more people one \"the one server\" you have to make the world bigger and I don\'t think level designers would like your idea that much

whereas if you \"clone\" the server, then you can have as many people playing at the same time without making the world bigger.
So idealy your idea of unique server would be great, but I think several different servers would require much less work and be more efficient.