I’m not sure, but believe the DJ feature is new with the latest version of iTunes. @georgekopp played with it for just a few minutes on Saturday at the Coffee Zone and if I understood his explanation, it works likes this.
If Taisir is playing music (through the Zone ceiling speakers) from iTunes on his laptop and that laptop is on the Coffee Zone wifi network, I can see his play list from my laptop (or my iPhone) and “request” a song from his list. That song would then be moved up in the queue.
You can see how this could quickly get out of hand. An Elvis nut could take over the play list. Perhaps iTunes DJ gives you some control over that. Maybe a limit to 3 requests or something.
But it looks like fun way to add some interactivity to the morning coffee experience. Stay tuned.