iTunes Genius - A feature of iTunes that provides two main features: creating playlists from your existing iTunes library and suggesting new music at the iTunes Store based on the music you like in your iTunes library.
The first feature, creating playlists, is designed to automatically create playlists of songs you already own that will sound great together. This is a different, more involved process than creating Smart Playlists, since this isn't just based on sorting criteria, but rather claims to actually account for what songs will sound good in what order.
The second, much more advanced feature, is similar to the functionality offered by services like Pandora, which use your preferences about certain bands and kinds of music to suggest new bands that you may enjoy. The feature integrates with the iTunes Store to allow you to quickly purchase the new music.
For both services to work, you must share some information from your computer with Apple. Both also use this information, plus that shared by other iTunes Genius users, iTunes Store purchases, and other data to make recommendations.
ITunes Genius is quick to set up and can also be hidden or turned off completely.
ITunes Genius functionality was added to iTunes with version 8.0, release on Sept. 9, 2008.
