I think because it takes so little effort. Even in an MMO, you have to man your character to do anything. On twitter all it takes it for at least one person to

I think because it takes so little effort. Even in an MMO, you have to man your character to do anything. On twitter all it takes it for at least one person to be tweeting at a given moment to ruin the other community. Plus, people on WoW would be paying a subscription, people are much more risk averse when they pay. Social media is free, and there's little to lose for most people.