What? Don't you read T-shirts?
The quote doesn't show up on the "Memorable Quotes" page for the movie Roadie on the Internet Movie Database site, but it's a memorable quote just the same, even if I'm the only one who remembers it. (Perhaps one reason is that it's a highly forgettable movie.)
Of course I don't only read signature files. I read T-shirts and just about anything else that might have some sort of identifying slogan. But it would seem that the days in which people actually identified with the slogans on their T-shirts are long gone. I've been known to stop people on the street who are wearing shirts with a picture of Che Guervara on them (or, for that matter, Bob Dylan) and ask them who the person on their shirt is. More often than not the answer is "I don't know".
A note on the context:
In the movie, the hero, a country hick, but a very adept rock roadie picks up a groupie hitchhiker on her way to New York. She wants to become a groupie for Alice Cooper. Our hero doesn't know who Alice Cooper is (even thinking he's a woman), and upon being asked, the groupie hitchhiker responds "What? Don't you read T-shirts?".
Go to: ... and I'll show you who you are, or
Go to: On regaining a cyberdentity.