A hypothesis for investigation is that screen reading is an impediment to understanding. Conventional reading develops distinction and concentration. Reading on displays tends to confusion and distraction.
Eric McLuhan’s Fordham Experiment with film (albeit more of a demonstration) seems to show that light on, light through alone is significant. And that would just be comparing reading on a paper page versus an eReader.
At a major newspaper’s Site, there might very well be animated popup ads demanding attention, flavoring the experience more like the Star Wars cantina than a library. And there’s no location at a newspaper Web Site. In the paper copy, news, opinion, sports are in different neighborhoods, immediately indicating value and relevance. Online, everything and anything resides in the same one click away long house. With print reading, everyone is literally on the same page; the physical experience is identical for all. Published through the Internet, text differs according to screen size, specs and configuration. For Online reading, it’s very likely that ads and suggested Pages will vary from user to user.
A high level of literacy was an important factor in the American Revolution. Any George III of the future will be secure in knowing that when his Thomas Paine writes Common Sense, very few will even try to read it on a small screen. And for most of those that do make the attempt, something will appear over to the side about an actress in a bikini and that’ll be that.