In addition to the usual security and bug fixes (including one that sounds pretty ominous: “maliciously crafted movie file may lead to an unexpected application termination or arbitrary code execution”), there’s now a Genius playlist feature.
In a way, Genius Apple’s way of heading off services like Slacker and Pandora. By creating a well-mixed and thematic playlist of out of your music collection you bring songs to the fore that you may not have listened to in years. While that’s not very impressive in an 8GB device like the Nano but fairly impressive in a 100GB collection on a desktop. The Genius Sidebar, connected to the iTunes Store, is also a “big, fat iTunes money tree” and is even more visible than the old iTunes Store bar that appeared at the bottom of iTunes. By suggesting thematically linked music choices every playback could turn into a sale.
We all know how what Genius is all about, but now it can be accessed on your Apple TV holding down the play button while a song is playing.
Either grab the update manually via Software Update, or wait for your Apple TV to prompt you.