A few weeks ago, gamerDNA made a push to get 500k gamers to take the Bartle test located on their site. Not only did they crush that number, but they've put the statistics to good use. In an interesting research article by Sanya Weathers (who was just recently on the Massively speaking podcast), you'll notice some fascinating results combining the Bartle Type of gamers as it pertains to their Warhammer Online class choice.
First off, this article shows the interesting distribution of class choices in WAR (from the people with that information in their gamerDNA profiles). Then that information is broken down to show gender preference per class and ultimately the Bartle Type in relation to each class. The entire article is certainly a worthwhile read, and says a lot about the balance of the game's classes and how the game can appeal to as many people as it has. Hopefully, as hinted in the article, gamerDNA will do research like this for other popular MMOs in the future.