MZRT by Ryan Leslie - An unlimited track album served as one single/month for life
Noiseblend - One-tap music for every occasion, with Spotify Premium
throwaway - throwaway is an in-browser messaging app.
22tracks - DJ curated Spotify playlists on iOS
Posiviber - Start a page, share the URL, get comments.
Spotify - Map shows when two people play same song at same time