"Unlike your average video game, which arrives on store shelves with a pre-defined scope and story, MMOs are an ongoing, evolving experience. (That World of Warcraft box you picked up four years ago bore only a faint resemblance to the game you're playing today.) Every time you log on, there's the chance of a completely new experience. Perhaps a recent patch introduced a new zone for play. Perhaps a recent patch introduced some unpredictable bugs. Perhaps your friends have decided to stage an in-game dance competition in the middle of your opposing faction's city. You won't know for sure until you log on and see -- and even after years of playing, you may encounter something in your favorite MMO that will surprise and delight you."