The brand new feature on the iTunes 8.0 is the possibility to create automatically a playlist, called the “genius Playlist” right on your device. Once you have synced you iPod or your iPhone with iTunes 8.0, you can create the playlist on the fly.
Based on algorithms on audio profiling, metadata matching, end user tastes and the list of songs that you have on your device, it will automatically create a playlist, just like Pandora and last.fm.
The results depend entirely on your music collection. If you create a Genius playlist on your computer, iTunes will give you a playlist, and some other songs that you don’t have but you might be interested in.