World of Warcraft (commonly abbreviated as WoW) is a massive multiplayer online role-playing game (MMORPG) developed by Blizzard Entertainment.

It is the fourth game in the Warcraft series, excluding expansion packs and the cancelled Warcraft Adventures: Lord of the Clans. The Warcraft games are set in the Warcraft Universe, a fantasy setting introduced by Warcraft: Orcs & Humans in 1994. World of Warcraft itself takes place within the world of Azeroth, four years after the events at the conclusion of Blizzard’s previous release, Warcraft III: The Frozen Throne. World of Warcraft’s release celebrated the 10th anniversary of the Warcraft franchise.

Although its initial release was hampered by server stability and performance issues, problems which still intermittently recur, the game is widely regarded as a success, being the world’s leading subscription-based MMORPG. On November 9, 2006, Blizzard announced that the subscriber base for World of Warcraft has reached a new milestone, with 7.5 million players worldwide.  An expansion pack called The Burning Crusade has been announced for release on January 16, 2007.
As an MMORPG, World of Warcraft is a radical departure from the standard real-time strategy wargame style of the other Warcraft games. As with other MMORPGs such as EverQuest, players control a character avatar within a persistent gameworld, exploring the landscape, fighting monsters and performing quests on behalf of computer-controlled characters. The game rewards success through money, items and experience which allow players’ characters to improve in skill and power. In addition, players may opt to take part in battles against other players, including both duels and fights against player characters allied with an enemy faction.

Many quests and monsters through the early and middle stages of gameplay can be conquered alone without the help of other players, particularly if the player’s character is higher level than his opponents. Other portions of the game, such as its instanced dungeon areas, are designed to require players to work together for success. Dungeons are designed for parties ranging from two to five players, up to significantly more difficult "raids" (a term originating from EverQuest gameplay) requiring up to a maximum of 40 players. The highest level, most complex dungeons and encounters are designed to take raiding guilds months of playtime and many attempts before they succeed.

In particular, the game areas designed specifically for level 60 characters are generally much more raid-dependent (and time-consuming) than the relatively more casual experience of advancing one’s character from levels 1 to 60.[3] The majority of World of Warcraft’s endgame content (i.e., content specifically designed for level 60 characters) requires raiding, with raids making up the bulk of the game’s development since release.

Because characters cannot currently progress in experience level beyond 60, gameplay focus at that level typically changes for players wishing to further improve their combat power and effectiveness. Since combat and quests at level 60 earn the character money and items, but no experience, characters improve by continuing to upgrade their equipment. With few exceptions, the most powerful gear in the game is earned either as PVP rewards in battlegrounds, or by fighting consistently over a long course of time in the highest difficulty raid instances. Large PvE raids normally take a few hours to clear entire dungeons, such as Molten Core, Ahn’Qiraj, and Blackwing Lair. Because of the extreme damage monsters at this level of play can inflict, a common practice is to equip with ’resist’ gear, meaning equipment specifically designed to maximize a character’s resistance and defense against the opponents he expects to face in that particular raid, such as equipping items with high fire resistance before facing a raid involving monsters that primarily deal fire damage. It also helps to improve a character’s reputation for factions associated with the instance, to make sure the character has enough cash saved up for repairs, and to purchase consumable items for use within the instance. For example, the newest 40 man instance, Naxxramas, requires the right reputation level to be allowed to enter the instance without expensive material costs.