This article on the 25th anniversary of the Walkman explores some of the fascinating social fallout from the rise of personal stereos.
"The Walkman was critical in altering the rules of being with other people," Schiffer says. "People thought it was rude to listen to music in public. Now our standards have eroded to the route we've gone down with cell phones, which is to sanction rudeness. We are losing sociability."