World of Warcraft has been compared to many things over the years. Everquest at first, then later, crack. But I don't think I've ever seen it compared to street gangs in LA.
Earlier this year, scientists from the US and China published a paper called "Human group formation in online guilds and offline gangs driven by a common team dynamic". Which does a neat job of summing up the paper's contents.
Basically, there's a mathematical model, a "a common team-based model can accurately reproduce the quantitative features of [WoW guilds and gangs] simply by adjusting the average tolerance level and attribute range for each population". So WoW guilds and gangs run on the same mechanics.
And it took scientists to come up with this? Crips and Bloods, Alliance and Horde...it's right there in the colours when you sign up, let alone whatever happens later on.
Human group formation in online guilds and offline gangs driven by a common team dynamic [Physical Review E, via Slashdot]