According to Bill Fulton, some of the most over-looked aspects of online game development today are design mechanisms to discourage players from acting like jerks. Rather than merely acquiescing to the reality that in any large game communities, there are just going to be a given number of dickwads, Fulton suggests that this accepted reality is nothing more than the result of faulty design. Developers can figure out ways to discourage or circumvent this kind of behavior, Fulton says, if they just put some thought into it.
Why does this even matter? According to Fulton, when immaturity and asshattery is allowed to rein supreme, it discourages large swaths of a potential player base from continuing to play, or even from signing up in the first place. Certain demographics, like women or older gamers who get enough childish antics from their kids, are especially resistant to this kind of behavior. If you look at a game like World of Warcraft, which is so eminently successful in these demographics, they've implemented a number of elements (like profanity filters, graveyard rez's, and reactive city guards) to keep the idiots at bay. When you're trying to emulate WoW's success, it's an feature set you'd be remiss not to include.