Dramatis Personae

Just like real life, there are basically jocks and dweebs. However, in virtual reality, you get to decide how you're going to turn out. Warriors and Hunters are the jocks of World of Warcraft. Priests and mages are the dweebs. Paladins and Druids can serve any number of functions. The overarching game strategy is to

1) Kill before you are killed (Damage per second {DPS})
2) Be so buff the other guy gets tired and dies (Tanking)
3) Keep another player alive long enough to keep you alive by proxy (Healing)

Lets just say there aren't too many full healers that are brave enough to face a battlefield, so in general the strategy is of the first or second variety.

Nick Yee did an interesting study on class and gender, as well as class and age.