I've read a very interesting article about the difference between real books and ereaders.
TL;DR : we may inconsciously gather more informations than we think from the phisicality of the books, something which is lost with ereaders.
http://www.wired.com/2014/05/reading...-versus-paper/
On my own level, I would like to add something. When I first started to read ebooks before buying a Kobo, I was using FBReader. FBReader has a very very nice feature, never seen anywhere : in the footer of the page, there's a very subtle gauge which shows you your position in the current book. This gauge (or progress bar) has mark for every chapter. This is very subtle, so not disturbing while reading. But I started to realize how useful it was. I was having a clear vision of the book, of its chapters structure, of my position.
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I'm really sad that there's no such feature on my Kobo. I really miss it.