This article led me to this post by Seth Godin.
He has become powerful enough to leave traditional publishers behind, focusing on direct sales to his audience. The question being, how many could do that successfully?
Here's a commentary on it. And an audio interview (MP3 file).
An interesting detail: we see Seth Godin, one of the world's most successful entrepreneurs/writers/speakers in the world, and we don't think maybe he wasn't always. But he says in the interview that between 1985 and 1999, he failed at "at least thirty significant projects". Wow.
The first-linked article mentions that in the US alone, there was over a million book titles published in 2009! Wow, that's a sobering thought for a writer.
Interestingly, less than one third of those were published in the traditional way, the rest are print-on-demand and such. That's almost double that of 2008, which was double of 2007. Talk about a growing medium.