Ebooks have enjoyed a popularity spike, going from 3% of sales in 2009 to 9% so far in 2010. If we go back to 2007, the curve is pretty alarming (for traditional booksellers): .6% in 2007; 1.2% in 2008, 3.3% in 2009, 9% now.
(Citation.)
Any traditional publisher/bookseller might look on this curve in a panic and extrapolate that, at this rate of growth, paper books will die sometime in 2012 as ebooks take over 100% of the market.
Of course, this is nonsense. We will have certain paper books probably forever, at least through the lifetimes of those living today.
Anyway, what I'm wondering is, how do you know when to start rounding off this curve, and how it might plateau?
Is there any predictive math that might guide us?