When a person defines themselves by the products they use. This is not unlike the pepsi v. coke arguement or claiming one chain restaurant is better than the rest. Except for the fact that most of us stop caring at the age of twelve. This is usually due to said person having no discernible personality.
Social Leper: "OH EM GEE I just got a Mac arent you jeeeealous? those comercials with that cool guy and that other guy liek totally sold me on it. Macs are liek soo totally better than PCs. Now im like totally going to make my album on this thing... how do you turn it on?"
Rest of the World: *YAAAAAAWNSKIES* Another boring person with Bland Loyalty issues.