this is taken from their website...
"Is Guild Wars an MMORPG (Massively Multiplayer Online Role Playing Game)?
Guild Wars has some similarities to existing MMORPGs, but it also has some key differences. Like existing MMOs, Guild Wars is played entirely online in a secure hosted environment. Thousands of players inhabit the same virtual world. Players can meet new friends in gathering places like towns and outposts where they form parties and go questing with them. Unlike many MMOs, when players form a party and embark upon a quest in Guild Wars, they get their own private copy of the area where the quest takes place. This design eliminates some of the frustrating gameplay elements commonly associated with MMOs, such as spawn camping, kill stealing, and lines to complete a quest.
Guild Wars takes place in a large virtual world made up of many different zones, and players can walk from one end of the world to the other. In Guild Wars much of the tedium of traveling through the world has been eliminated. Players can instantly return to any safe area (town or outpost) that they have previously visited just by clicking on it in the world overview map.
Rather than labeling Guild Wars an MMORPG, we prefer to call it a CORPG (Competitive Online Role-Playing Game). Guild Wars was designed from the ground up to create the best possible competitive role-playing experience. Success in Guild Wars is always the result of player skill, not time spent playing or the size of one's guild. As characters progress, they acquire a diverse set of skills and items, enabling them to use new strategies in combat. Players can do battle in open arenas or compete in guild-vs-guild warfare or the international tournament. Engaging in combat is always the player's choice, however; there is no player-killing in cooperative areas of the world.
Finally, unlike existing MMOs, all characters in Guild Wars inhabit the same virtual world -- they are not divided onto different servers or shards -- so players can always team up with or compete against any other player in the world."