Spotify recently announced to the world their new discover tab. This feature was shown back in December 2012, but is still yet to launch to the world until now!
“We know you’ve all been eager to see the discover features rolled out so we just wanted to let you know we’ve begun rolling out the brand new Discover tab to a very small percentage to folks in the UK and Nordic countries on the desktop application of Spotify. We’ll be rolling it out to more customers in the coming weeks.”
Spotify also lists documentation for the feature on its developer site.