Spotify's "Mix" feature now has an option called "Smart Reorder" that can automatically sort users' playlists based on beats per minute (BPM) and key, organizing songs for the best flow from one track to the next. It builds on the existing Mix feature in Spotify and, along with transitions between songs, which were introduced in August, users can now effectively have an automated DJ mix their Spotify playlists for them. The "Smart Reorder" option, announced on Wednesday, is available now in the Spotify app for Premium subscribers. To try it out, open a playlist and tap the "Mix" button then "Edit." The "Smart Reorder" button should be at t …Read the full story at The Verge.