One of the defining aspects of reputation is the faction system. All reputation is tied to a specific faction, of which there are many. The main factions in the game are the Horde and the Alliance, which are at perpetual war with one another. Players of the Horde faction will never be able to earn reputation with Alliance, and the same in reverse. This is at a basic level of game mechanics, where players simply do not have reputation tracks with the opposing factions. Horde players will never have an associated Alliance reputation track. These factions are considered “kill on sight”.

There are other factions present within the game, each are usually under a major grouping. Horde players, for instance, have all the Horde cities (Orgrimmar, Silvermoon, Thunderbluff and the Undercity) maintained under a grouping simply called “The Horde”. Other factions are similar grouped: some of the major groups are the Steamwheedle Cartel, who control the goblin cities of Azeroth; and Shattrath City, which maintains Lower City, Shat’ari and Scryer vs. Aldor. The last two factions, Scyer versus Aldor, are diametrically opposed [2], as are several others. Reputation gains with one faction results in immediate reputation loss with another faction.

Each individual player maintains a reputation track, but not all players may have access to specific factions. This is generally due to lack of character development, in the case of a player not seeking to discover a particular faction. Since the release of The Burning Crusade, some of the older level 60 raid-level factions have been neglected; it is entirely possible that new players may never discover those factions. When a player discovers a new faction, the player will be shown a status message informing the new reputation level. While some newly discovered factions begin at Neutral, that is not the rule. Some factions are discovered at Friendly, or even at Hated. [3]

Reputation gains are often subject to “spillover” to other factions within the grouping. For example, when a player of the Tauren race completes a quest for the capital city of Thunder Bluff, reputation is gained not just for that city, but may also be earned for the Horde faction. This spillover is often invisible to the player, as a status message may detail the reputation gain for the major faction, but the spillover may not be detailed.