Magic Playlist - Get the playlist of your dreams based on a song

buddybuild - Buddybuild ties together continuous integration, continuous delivery and an iterative feedback solution into a single, seamless system. With buddybuild, you can focus on what matters most: creating awesome apps.

Spotalike - Spotify playlist with similar songs, according to Last.fm

Twitter Audience Insights - Loads of info about your followers, their interests, & more

Playlist Machinery - Tools that help you create & organize your Spotify playlists

User Interviews + Lookback - Target any audience & record their feedback