If you start streaming music via AirPlay from an iDevice (iPhone 4s in my case) to the ATV, you can not only skip forward/back within the music "app" of that device, but you can also do so with the ATV remote itself. How & why?

You obviously have to use the ATV remote to skip songs when AirPlaying from a computer running iTunes on the LAN or streaming from iCloud, but I'm surprised that the ATV will basically control the Airplay stream from my phone.

It's evil black magic.

I thought it was FM. Today is a good day- I learned something.

Either way, it's controlling the streaming source via the app.

How: Two way communication over network.

Why: If your phone is charging, in another room across the house, etc. you can still control it.