Looks like YouTube is continuing its evolving nature and with a new experiment into YouTube Radio. This expands on the current YouTube Mix and YouTube Music Key. YouTube Mix is the nifty little playlist function that creates a mix of music videos based on the video that is currently playing. It is pretty cool and kind of fun to have playing on a side screen like a tablet while at your desk. YouTube Radio is a similar take on YouTube Mix that is described as “A non-stop radio station based on the current video. You can like, dislike and dismiss videos to tailor  your Radio Station to your taste.” Basically it will be like all other streaming music radio services where the like and dislikes will effect the outcome of the streaming songs in the future on the station.
It would appear that the testing is pretty limited in scope for the time being and there are many details roaming around beyond the screenshot and report that came from Google Operating System. It isn’t even known if this is where YouTube Music Key will be heading or the YouTube Mix offers. My best guess is it will be a mix of both and Music Key will be the paid subscription that is ad free, allows offline playback on mobile, background listening and you will get a whole YouTube Radio offering inside.
Source: Google Operating System Via 9to5Google