MMO games need to be designed for two reasons: entertainment and money. The need to keep the player entertained, as well as make a profit. If the game does well in one area but not the other, or if it does measly in both, it often fails. Therefore game designers need to be vigilant when designing their games, so that they keep both boxes ticked at all times. This is where you say: "hey wait a minute, the business model has nothing to do with game design!?!?!"... if only that were true.
The design of the MMO must play to the business model and vice versa. An excellent example of this is Wizard 101. The game is designed so that certain areas of the fantasy world are 'locked' and you need to buy in-game tokens in order to unlock them. I know it sounds stupidly simple (and it is), but if the game map hadn't been designed into 'lockable areas', they would of had issues with their business model. In the case of Wizard 101, the alterations to their game design to incorporate the business model were rather minimal. The player's experience is impacted in a very small way.
Lets now take a more extreme example, where the business model greatly impacts on the game design. Since I'm not a big fan of WoW, it seems only fair that I pick on it. WoW unfairly gets a lot of attention on this blog when talking about bad game design. Apologies to the WoW readers.
WoW uses a subscription based model, and therefore makes it's money by enticing players to 'hang around' as long as possible. The game employs multiple techniques to achieve this goal, but the end result is the same. The player must spend a large amount of time to gain a very small step in progress. This could be in the form of grinding to gain a level, an item or an achievement. In the time it takes a casual player to get from level 1 to level 80, Blizzard has just made 4-8 months worth of subscription fees off them. In the time it takes to deck a character out with all the most awesomely powerful items, another 2-4 months. You get the idea... Essentially the game design plays to the business model, and it does an excellent job of it.
Where the problem lies, is what happens if all you want to do is skip the formalities and get to the endgame? You might want to only play WoW so that you can do raids with your mates. Unfortunately incorporating such a design change would conflict heavily with the business model. Blizzard would no longer make the 4-8 months worth of sub fees off you. Such a design change would be considered infeasible and bad for business. What does that mean for the gamer? It means you have to pay the money and put the time in or tough luck.
This brings me to my next question. Which business model has the least impact on the game design?
I haven't fully done my research on all available MMO business models, but I know from experience that the Guild Wars 'pay upfront' model has very little impact on the game design. ArenaNet could change what ever they liked about the game as long as the entertainment value stayed the same or increased. Their designers have one less thing to worry about when taking your entertainment interests into account. Ultimately the gamer benefits.
I know there have been many discussions about what business model works best, and this post is not about reigniting them. I just wanted to provide something else to think about when choosing an MMO :P