If any of you have the Xbox 360's HD DVD Player, you may have noticed the 'HD-DVD' as a new storage device section under Memory on your System Blade. Before you ask, NO!! It can't be used to store game content, arcade titles, and so on.  You can only delete items from this memory area; your games won't even see it.  This memory area is part of the HD DVD special programming, and it only accessible by the Xbox 360 HD DVD player.  So, if you put in bookmarks from the HD DVD's that you play, you'll use that memory, as seen in the system blade. You can delete that content, it will delete the bookmarks, like if you RENTED the movie, it would mean you don't need the information again since you rented the disc.