"CUPERTINO, California - April 9, 2007 - Apple(R) today announced that the 100 millionth iPod has been sold, making the iPod the fastest selling music player in history. The first iPod was sold five and a half years ago, in November 2001, and since then Apple has introduced more than 10 new iPod models, including five generations of iPod, two generations of iPod mini, two generations of iPod nano and two generations of iPod shuffle. Along with iTunes(R) and the iTunes online music store, the iPod has transformed how tens of millions of music lovers acquire, manage and listen to their music."
It's interesting to see how a single little device like the iPod could spark such a massive change in the way people listen to, and buy media of all kinds, not just MP3s.
All in all, there was probably some disappointment that the 100,000,000th unit didn't come signed by Steve Jobs and/or come in a gold case, but it seems like it's only a matter of time until the 1,000,000,000th unit ships.