In addition to the chat feature I would love to be able to inject my voice into the app and intro songs etc. like a radio DJ does. With all smartphones and tablets having mics nowadays you wouldn't need to purchase extra equipment.
I have always wanted to be a DJ and with access to the Spotify's library this would give people a chance to do requests and intro songs they love etc.
I hope this is something that can be considered for future versions of the app.