The in-game plague that temporarily harassed citizens of Blizzard's World of Warcraft wasn't a piece of malicious code, it was a bug. The citizens of Second Life aren't so fortunate. Clickable Culture says that the "Red Wing" virus has returned to the game. This isn't the first time Second Life has had virus issues. I'm not sure what's worse, a crippling in-game bug that wipes out entire populations or a virus that pops up with lewd pictures of men behaving badly.

Second Life Virus Defies Containment [Clickable Culture]
Virtual Humiliation Virus Contained [Clickable Culture]
World of Warcraft Still Infected