There were transistor radios with little earplugs way back in the sixties, but the idea of having both ears closed up like that and listening to something which nobody else could hear was a bit strange. Of course, at home you could clamp a gigantic pair of headphones on, but that was not common. The Walkman was revolutionary in that it meant that the music you listened to was for you alone. It was not intended to be shared. Today, it is very common to see people with earphones in listening to MP3 players, but back in 1979 the idea was radical in the extreme.