Phil Freeman on the use and abuse of Iron Maiden T-shirts:

Since the mid-1960s, marketing has been more about individuality than conformity. Advertisers stopped saying “be one of the in crowd, buy our product” and started saying “break free from the herd, buy our product.” Nowhere has this been more prevalent than in the music industry, which almost always tries to sell its latest faces as rebels. Think of the black leather jacket, which has been a crucial component of the costume all the way from Elvis to the Ramones to George Michael and Color Me Badd. Like leather jackets, metal T-shirts are being purchased as components of an all-purpose pseudo-badass posture. But this strategy only works when they can be separated from any actual connection to metal. This is done by going retro. Ashlee Simpson would send an entirely different message if she walked onstage in a Slipknot shirt, and her management and her stylists know it. A shirt promoting a current act carries a much greater weight of implied endorsement, in the mind of the larger non-metal public, than does one advertising a veteran band with a pop-cultural presence that transcends the self-contained and insular metal scene, like Judas Priest, Black Sabbath or Iron Maiden.

It's a long post, but the whole thing is worth reading.