In mid-January PEW for the last few years has been running a survey to find out about people having an ereader or a tablet. To me it always looks like geometric growth, in other words, we have moved out of Chris Anderson's long tail concept and are now in the "mainstream," with ebooks and tablets. Over the last three years, each year the number of tablets in use have just about doubled, from 5% in 2010, to 10% in 2011, and now 19% in 2012. And ereaders are pretty much the same (10% in 2011 and 19% in 2012). I also think that when you put readers and tablets together it becomes even more impressive, as of January 2012 it is estimated at 29% of adults have either a tablet or a reader. Then of course there are people like me, who have multiples of each that we work and experiment with (although PEW never calls me). I know to many when they read numbers like 5%, they thought it was no big deal, it's a rarity, but that is hard to continue to say when numbers become something like a third of the population. Also as Penn & Zalesne stated in their book Microtrends, "In today's mass societies, it takes only 1 percent of people making a dedicated choice - contrary to the mainstream's choice - to create a movement that can change the world" (2007, xv). Well ebooks have now gone far beyond that 1% concept, look around and you will notice something that is in use by 19% (approaching 1/5 of the adult population), people around you have ebooks and are reading them.
(image source: http://wirelessandmobilenews.com/2012/01/tablet-ownership-doubles-due-kindle-fire-prices-ownership-wealthy.html)