This cool prototype device was designed by Jordi Parra and works with the Spotify streaming music offering. The cool thing about the design is that Parra has figured out a way to share playlists with physical discs that are sort of like giving a friend a mix tape back in the day. The mix tape in the case of this Spotify offering is a little wood disc.
The wooden disc has a RFID tag on it that is linked to a specific playlist on Spotify. When the disc is crammed inside the Spotify supporting radio it links to the playlist and starts to play it automatically. That would mean you could just hand these discs out to pals or mail them and share your playlist process all you want.
The prototype device has to be hooked to a computer to work, but the designer thinks that in the future it can be made into a standalone radio. Parra thinks that he can use Arduino and an Arm processor inside his prototype to make the thing standalone. The project may wind up on Kickstarter to come to the real world so keep an eye out.