Excerpted from Blizzard's Official Announcement

World of Warcraft i, a massively multiplayer, online role-playing game set in the Warcraft universe.  World of Warcraft will allow thousands of players to adventure together in this epic world and will provide them with a new, in-depth perspective on familiar lands, former battlefields, and heroes from the legendary universe. In addition, World of Warcraft will introduce new, uncharted territories and foes never before seen by followers of the series. World of Warcraft takes place four years following the aftermath of Warcraft III: Reign of Chaos, where a great tension has settled over the ravaged world of Azeroth.  As the various races begin to rebuild their shattered kingdoms, new threats, both ancient and terrifying, have arisen to plague the world once again. Players must explore the lands of Azeroth, forge fellowships with other players, and build their strength in order to prevail. 

"World of Warcraft is our largest undertaking to date," according to Mike Morhaime, Blizzard Entertainment president and co-founder. "We are extremely focused on increasing the scope of the Warcraft universe, giving gamers an incredibly dynamic online gaming experience complete with endless possibilities." 

An action-packed combat system delivers fast, furious combat against multiple opponents, while minimizing delays between battles to keep players on the move. A rich, evolving story and questing system will keep players engrossed as the world is regularly updated with new content.  Fully customizable character classes, innovative races, and thousands of weapons allow for a truly diverse gameplay experience that will appeal to both hard-core and novice gamers alike. A simple, intuitive user interface will allow players of various skill levels to easily join the adventure. World of Warcraft also features support for advanced graphics hardware, giving the player superlative graphical enhancements, as well as a sophisticated, massively multiplayer network architecture capable of supporting thousands of players in a world simultaneously.