“ Still, at any share over about 20%, it will be more economical for an established author to self-publish through ebooks (where they can retain 70% of sales revenue) rather than working through a paper publisher (where they get at most 15% of revenue). When we hit that point on a sustained basis, I expect that a lot of authors will move to electronic publishing quickly.”
Good point by Michael Mace, at Mobile Opportunity.
eBooks made up 27% of book sales in the first quarter, which is likely the high water mark for the year. Give it a bit and ebooks sales will be steadily over the 20% tipping point.
Source: mobileopportunity.blogspot.com