Left: The iconic images associated with each class World of Warcraft currently has to offer
Every player in WoW can pick one of eleven classes. Each individual class has unique characteristics and abilities which make for a diverse set of playstyles. Additionally, when considering group composition, one must take into account the synergy among various classes.
Of these eleven classes, there are three different roles, known colloquially as "Tank," "Healer," and "DPS."
Tanks
Broadly speaking, a tank's role is to make sure all the enemies ("mobs") are not attacking anyone else. Often times, there are either too many mobs in an area or there are mobs that complement a boss, which results in a raid needing two tanks to sort out who will tank which mobs.
Healers
Players who opt to take the Healer role are responsible for making sure no one in the group dies. A healer's biggest challenge is making sure not to run out of "mana" - the resource used to cast whatever spells are needed to keep the group alive. In a group setting, there is a balance between choosing when to heal and on whom that heal should be used. Do you risk the tank dying in order to heal a DPS? Do you keep everyone at full health at the risk of running out of mana?
DPS
DPS stands for “damage per second” and players in this role are the main source of damage against enemies. Throughout a fight, DPS players need to prioritize any number of targets and avoid as much damage as possible. While healers will certainly help, DPS are the most prone to boss mechanics that will cause too much damage to heal through. Being a good DPS player is a combination of knowing one’s own class and knowing a boss encounter well enough to know how to not die.
Above: the blue bar shows a character how much mana s/he has left. The lower the mana, the more coservative a player must be with healing.
Right: one type of interface that might be used to keep track of players' health or various buffs (good things) and debuffs (bad things). Using such an interface can help healers quickly and easily identify who is low on health, who is about to be low on health, and who is safe for the time bein.
Above: sample point-of-view shots from a tank's perspective. Notice how all the enemies are faced toward the tank, attacking him instead of anyone else. Whether fighting a single boss or a group of enemies, the tank's job is to keep them from attacking the rest of the group.
Left: an example of how DPS might evaluate their performance on a given fight. The numbers indicate the total damage done by a given player, that player's actual damage per second, and the percent of total damage done by that player.
