Imagine the headline: "[Your Name Here] wins $10,000 for downloading the ten-billionth song from Apple's iTunes Store".
For that exact reason, watch what you're buying now. Considering the song that you downloaded will likely be mentioned prominently in the ensuing news flurry, do you really want your name permanently attached to something like the Insane Clown Posse, or even worse... Taylor Swift dfjb dfoigdfvb dfogifbn dfgiofb DAMMIT, Let go of the keyboard Kanye!
If you want to make things a bit more strategic, you can view Apple's 'Countdown to Ten Billion' sub-page. We should mention that the $10k comes in the form of gift vouchers to the iTunes store. How exactly you'd ever spend that much money on downloading music remains to be seen.
Apple also took the time to reveal which song has been the most popular since they opened iTunes back in 2001. That accolade went to The Black Eyed Peas, with "I Gotta Feeling", which, according to Cracked.com, is officially the worst song ever written.
Pats on the back all around people!