TestTube, the ideas incubator for Youtube. It’s where YouTube engineers and developers test their work and allow users to get a first hand look of whats cooking inside.
Youtube Disco as described from its creators is a place where users can make playlists and discover new artists and music videos.
Disco is neither ground breaking nor spectacular in its functionality. However it might help few users who like to hear/see assorted playlists of various artists. The other downside to this Disco project is that the search results are not always upto the users liking.