Well, there have been many discussions about this topic in the past, esp. in the early days, when the game was just released.
This thread is one example. I'm not sure if it's the most complete thread but it's the most recent one and the only one that I actively participated in myself and (thus) the only one that comes to mind right now. Of course, if this doesn't answer (all) your questions, feel free to ask for more explanations...