Apple has released an anticipated firmware update for the Apple TV, v6.0. The main addition is support for iTunes Radio, Apple's new streaming music service, also available on Mac, Windows, and iOS devices. Some other changes include podcast sync, access to shared Photo Streams, and the ability to listen to music purchased from the iTunes Store.
A potentially more significant addition is the ability to AirPlay content from one person's iTunes/iCloud account to a separate person's Apple TV. In that scenario, Apple ID authentication is handled through the first person's iPhone, iPod, or iPad, rather than the Apple TV. The feature appears to borrow a concept from Google's Chromecast, which is likewise untethered to user accounts; instead, compatible iOS, Android, and Chrome apps detect a Chromecast on a local Wi-Fi network, and can cue the dongle to fetch the content online.
Apple is rumored to be working on updated Apple TV hardware
as well. What it might include is uncertain, but it's believed that it could ship as soon as next month, around the same time as Apple launches new iPads and Macs. The v6.0 firmware may be meant to pave the way for the refresh.