I was going to say the same, Discover Weekly frequently really impresses me with some of its selections and I have discovered some excellent artists through it. I'm into electronic music - not what I would consider really obscure stuff, but certainly not mainstream - and many other recommendation systems seem top lump anything electronic together with mainstream "EDM" etc. (which is nothing like what I enjoy) whereas Discover Weekly makes intelligent recommendations of quite obscure stuff.

I assume it uses some combination of social data (e.g. music listened to by people who listen to similar artists as you) and the intelligent classification ability they purchased when acquiring Echo Nest. There was quite a good write up about it - I think it was one of these two: http://www.theverge.com/2015/9/30/9416579/spotify-discover-w... or http://qz.com/571007/the-magic-that-makes-spotifys-discover-...

I just wish it would save my previous weeks' playlists as sometimes I forget to listen to them and then they're gone!