80%. That's the market share Mike Shatzkin, a well-known consultant in the book publishing industry, is predicting ebooks might garner in two years:
Here’s an assumption that is not documentable; it is my own speculation. I think we’re going to see a US market that is 80% digital for narrative text reading in the pretty near future: could be as soon as two years from now but almost certainly within five. We have talked about the cycle that leads to that on this blog before: more digital reading leads to a decline in print purchasing which further thins out the number of bookstores and drives more people to online book purchasing which further fuels digital reading. Repeat. Etcetera.
We’re already at the point where new narrative text units sold are well north of 25% digital (percent of publishers’ revenue is lower than that, of course) and we are still in a period that has lasted about five years (soon to end) where the penetration of digital has doubled or more annually. (I italicized that to emphasize that what I’m talking about doubling is the percentage of sales that are digital, not the absolute number of digital sales. Several people misinterpeted that when I made to it previously.)
Of course, penetration will slow down before it reaches 100%. I’d imagine we get to 80% in 2 to 5 years, then then to 90% in another couple of years, with the last 10% stretching out a long time. How long did it take after the invention of the car before the last person rode their horse to town? - linkI think Mr. Shatzkin's assessment is a tad aggressive; I'm more comfortable with 80% in three years. : P