What if we added a "social mode" feature in music apps on smartphones?
Meet new people on the go
Seemingly introduce yourself without saying anything
A new way of social interaction
You would turn on your favorite music app and start listening. You also turned "social mode" ON and recorded a short voice message where you introduce yourself. You start walking in the park and you hear a notification. A random pop-up window appears with a profile photo and a recorded voice message introduction plays (or you press play). You hear a 10 sec message from the stranger that is somewhere nearby. If you are interested in meeting him/her, you look for them in your surroundings. If the message didn't impress you, you skip the notification and continue listening to music. Another notification pops up. And another. And another. You become sick of the notifications pausing your favourite song, so you turn OFF the "social mode" and continue listening to your favourite playlist. Nobody ever gets notified if you checked their profile or not.
There could be a feature allowing you to "connect to somebody's earphones" by enabling you to hear what they listen to at that moment. It should be enabled only if both users are in social mode and both agree to share the music.
Sharing running/walking statistics
It could also be combined with running apps so you can see how much did a person running next to you ran by now and what are their stats. It could be like a motivation for those lacking some.
Sharing social media accounts nearby
If a person wants to connect with people running in the park, it could turn on the "social mode" and share its social media accounts with people walking/running/sitting nearby.