Tap into existing stream?

[laruellef]

Would it be possible to tap/listen to some other user's stream?
Use case:
- upon login, user is presented a list of active streams
- user has choice to start his/her own stream or pick an existing one
- if an existing stream is picked, user starts listening exactly to what other user is listening to... (without ability to control it)

I think this could be an exciting collaborative feature...