How do you create your own mmorpg

I am not exactly sure how but I do know that if it is multi player you need to rent a server or have your own PC permanantly on and connected to the internet. Alternatively you could make the game only on-line during a certain time period. Well, I use Xtreme Worlds, which is probably the best mmorpg engine around. It's just a lot more stable and user friendly than the other engines (IMHO).