This all seems wonderful, and the system works very well. People get along, they accept one another, as evidenced by the tolerance for horrible typing skills, and the few bad ones seem to eventually just disappear. The question is why? Why are people willing to do so much for each other? Here are the reason that are apparent.
1) Well defined goals and common enemies with no real competition: EverQuest has a well defined, though never ending, goal. Gain enough experience to get to the next level. The way to gain experience is to kill your enemies. With a few exceptions the enemies are NPCs. You gain nothing by being better than the next player. You only gain by killing the common enemy. Joining a party truly helps everyone.
2) Returning the Favor: When people first start playing EverQuest, they all tell me the same thing. I was doing poorly until person X helped me. Then I started gaining levels really fast and doing really well. Eventually they feel the need to return the favor, and they will help the next newbie.
3) Feeling of community: People like to fit in. When they join EverQuest or games like it, they will pick up on the attitudes and behaviors of the people around them. The community started with a core of altruistic people, and they have taught the first wave of newbies, who in turn taught the next wave. This enforces the behavior described in # 2.
4) Trust has no cost: Since the world they play in is an illusion (though some may argue differently) trust is free. If someone betrays you at most you have lost some experience or some money, both of which are just numbers in a database. Since there is no way to force a player to do something in EverQuest, you can safely ignore those who are bad. People like attention, they will either change their attitude and play nicely or never logon again. This decreases the bad ones overtime and reinforces the positive players.
Through these for patterns the altruistic players are given positive reinforcement, and the non altruistic players are either loners, or quit logging in.