Just when we thought it had been neglected, the Apple TV (gen 2 and gen 3) receives a huge system update that is available right now. Some of the features include general performance and stability improvements, the ability to share photo streams, browse photos and comments and receive notifications of new contents. Users can now send audop content from Apple TV to AirPlay-enabled speakers and devices as well as iTunes account switching so you can (finally) access various iTunes accounts from one device.
Source: Apple