eMarketer estimates that nearly 50 million Americans used an ereader at least monthly in 2012. This year, the number of users is expected to increase 10.1% to 21.8% of internet users or 16.8% of the total population. eMarketer’s estimates of ereader users include those using devices with e-ink displays, such as Amazon’s Kindle and Kindle Paperwhite. Devices with an LCD screen like the NOOK Color are considered tablets. Read the rest at eMarketer.