Slackbox - Spotify playlist collaboration through Slack
Spotify.me - Beautiful analytics on your Spotify listening habits 🎧
Playlist Machinery - Tools that help you create & organize your Spotify playlists
Your 2017 Wrapped by Spotify - Relive all the music you discovered and loved in 2017.
PlaylistMap - Connect with Spotify playlist curators from around the world
Spotify - Map shows when two people play same song at same time