The lines are definitely blurry, because you can use a traditional tablet to read e-books, and you can use some e-readers to browse the web. That said, there are three key factors that generally distinguish them from each other. Tablets have full-color screens that project light while e-readers rely on e-ink, which is grayscale and much better for your eyes. Tablets can usually only survive a few hours on a single battery charge, while e-readers can last for weeks. Most importantly, e-readers don’t run apps. Functionality is much more based upon reading, whereas tablets are useful for plenty of other activities.