If I remember right, Amazon bragged that it sold 1,000,000 e-books during the last Christmas holiday after their latest version of Kindle came out. (This was before the Ipad appeared...)
What Amazon did not explain is that they counted as sales the books readers were downloading for free. Even free has a sales list of $0.00 in the receipt. I know, I pick up a few for my Kindle for PC program on my computer, so I am sure my pickings were included, though I did not BUY any actual e-books...
Forget where I read it, but I think it was Random House that is predicting e-sales will climb to 13% this year, and that is one hell of an increase from the 4 or 5% from 2 years ago. Still, 13% is still a long way from threatening print books...