Spotify says the Discover Weekly playlist is built based on the music that you listen to in addition to what other, similar users have been listening to. It’s designed to surface the lesser-known tracks and deep cuts, as opposed to just being a playlist of the most popular songs out right now. It’s available at the top of each user’s Playlist folder.
I'm very, very excited about this. That was one feature I thought Apple Music did well. But, I still love my Spotify. Prior to this, the weekly "for you" emails that I got from Spotify were spot on. So happy this is now built right into the app!