According to Apple, since Apple developed the new way for getting musics seven years have passed. Now the number of downloading songs is about to jump to 10 billion. For the milestone, Apple launched the $10,000 iTunes Gift Card. Once you luckily hit the 10 billionth song, the iTunes Gift Card would be yours. Watch out the countdown billboard, it might make you the lucky fellow.
You can get more details and rules from Apple.