"GPL is cancer"
GPL is one of the main reason why Linux desktop market share is below 5%. If that means it's a cancer or not is up to you to decide - but it's one of the reason most commercial - useful and needed - software is not ported to Linux. Which in turn ensure MS can do disasters with Windows still knowing users have little other choices but for the simplest needs. Under this point of view, Ballmer was utterly wrong - GPL is a great helper for Windows.