I have been reading a good book called The Shallows: What the Internet Is Doing to Our Brains I have found this books to be very interesting. It is full of research and science, but it is still readable and challenging.
One of the interesting things I was reading today was about the experiments that compared reading a book to reading the same text on a web site with hyperlinks. The results of several experiments shows that the more links you put on a page, the less the reader comprehends. Experiments with multimedia are even more dramatic.
If you are reading an article on the Internet, do not fall for all those hyperlinks, just read your article and concentrate on what you are reading.
So, the reason I read books on my kindle is that I find them easier to read, there are less distractions, and I can understand more of what I am reading. The kindle does not allow you to much more than just read, so there is no temptation to check your email, click on a link, or use a different app.