“Testtube is the trial runs of new Youtube.com features.”

They have a new services called:

Warp (Visually browse YouTube videos in the Fullscreen player.)

Active Sharing (Use Active Sharing to show other YouTube users what videos you’re watching)

Audio Swap (Use AudioSwap to replace the audio on your videos with officially licensed music.)

And

Streams (Join Streams to chat with others who are watching the same video you are.)

I created a Youtbe Stream. the name of stream is
Rap and Hip Hop. You can go here to see it or listen or add some nice song to hip hop stream.
There is not much people there yet, and even if users leave the room, the playlist stays.