It's pretty cool that you can throw music from iTunes to your Apple TV. But what if you want to share some music from the web or another source on your sound system. It's not that easy. Yes, you could run a wire to the system. But that is so 1998! I have been using Airfoil and Chromecast (audio only) to cast music all over the house. It's Sonos without the $2k tax. I have two Chrome's in different rooms which fills my house with tunes. Using Wifi, I can get a party rocking. All for just about $100 bucks.