A blog post was recently published on PaidContent.org on how e-book sales are growing quickly and how sales of paperbacks are declining. The post says that e-book sales have been strong in niche markets (romance, travel, etc.) but are quickly expanding into all major markets.
Some of the research came from the Association of American Publishers and shows the general increase of e-book sales compared to the decline of paperback sales. You can view the post here
Do you have an e-book reader?
Would you use an e-book in a classroom?