From the Smashwords blog:
Oh, wow. After I finished the previous post about how the number of self-published books is exceeding the number traditionally published books, I clicked over to the Smashwords home page to discover our word counter ticked past 500 million when I wasn't looking.
Six months ago, I set a crazy goal for Smashwords to publish one billion words by the end of 2010. I called the challenge our Billion Word March. At the time, we had just published our 150 millionth word.