Sleeve - Your currently playing track displayed right on your desktop
Magic Playlist - Get the playlist of your dreams based on a song
Uber Ride Request Widget - Embed the Uber experience in your app in a few lines code
Spotalike - Spotify playlist with similar songs, according to Last.fm
UnitedMasters - Creator tools for artists to get smart, get fans, get paid
Spotify - Map shows when two people play same song at same time