Instagram lets your friends see what you see. Foursquare lets them be where you are. Pinterest lets them bookmark what you bookmark. But what about when you find yourself having lunch looking over the bay and Otis Redding comes on? Or you walk into a cafe that plays Just Dropped In? Or you put on a hat and blast Willie Nelson out?
It would be fun having an app that lets you not only share what you see, but also, you guessed it, which song you hear. And not in a bootleg-ambient-noise sound quality mess kind of way. Full quality. It would recognize the music with a technique similar to Shazam and find a version online, maybe using Spotify, Rdio or Hype Machine.
Users of the app would then be able to use the stream as a mixtape of carefully hand picked songs.