As a comment to the excellent talk of Gunther Kress this afternoon,  I will draw your attention to a new study at the university of Stavanger:

Literacy studies – master

Is the book an endangered species? Are sms-messages destroying the English language? What were medieval books like? How do children learn to read and write? Who was Shakespeare and does it matter? What does reading do to our minds? http://www.uis.no/studietilbud/spraak_og_litteratur/master/literacy_studies/

And another study at the National centre for reading educaton and reserearch (Lesesenteret):  Digital reading
How can one teach students who hide behind their PCs and switch between Word, Facebook, Wikipedia and Twitter? An ordinary day for teachers has been completely transformed during the last five to ten years. Reading research at the University of Stavanger has examined the complete transformation of the classroom which has taken place over the last 5-10 years.  http://lesesenteret.uis.no/frontpage/news/article26458-3357.html