There was a lot of concern inside Sony that the Walkman would be perceived as anti-social, that's why it came with two headphone jacks, and the hotline feature

There was a lot of concern inside Sony that the Walkman would be perceived as anti-social, that's why it came with two headphone jacks, and the hotline feature which let others talk to you, via microphone, over the music. Both were essentially gimmicks and never really worked well, and were soon dropped.