Fascinating article (I love typography) by James Felici in CreativePro. I suggest you read the whole thing and take a look at the illustrations as well:
Whether on Kindle, iPad, Nook, or other LCD display, type suffers compared to print. So is good typography even possible for today’s electronic devices? From the standpoint of the craft’s two underlying principles — legibility and readability — the answer is “no.”
If you look at the size of the type most people choose for their Kindle, iPad, or any other device used for reading e-books, you’ll see that it tends to resemble that in books for people with vision problems. Logical enough, because when you’re reading an e-book — especially on a computer monitor — you do indeed have vision problems, compounded by poorly set type.
Enlarging the text addresses the first problem of screen type: legibility. When set in sizes considered normal for print on paper — 10- and 11-point — it can be a struggle just to decipher screen type. But making type larger by itself — enlarging it to, say, 12- or 14-point — does little to improve readability, because the low resolution and display techniques of computer and e-book reader screens prevent the fine character definition and spacing we’ve become accustomed to in print over the years.
The question of readability is not just an academic or aesthetic issue: Studies show that people read printed text 25 percent faster than on-screen text. What can we as typesetters do about this? Very little, as it turns out.
The concluding paragraphs are an eye-opener:
I am not a Luddite when it comes to onscreen reading, and I can see a day — it could be very soon indeed — when devices with reader-friendly display technologies make e-reading the functional equivalent of reading printed pages. Very high-resolution display devices already exist, although costs keep their sizes so small that they don’t provide a very pleasant or book-like experience (much less a magazine- or newspaper-like one). We can quibble about the aesthetic merits of print on paper, but that’s not the point here.
The problem today is that after 500 years of evolution, the “printed” word has taken a step backward in quality. According to “The New York Times,” electronic publishers are commissioning shorter books because their readers find it too tiring to take on longer works. Ever since I started writing for online magazines I’ve been obliged to write shorter pieces than in the past because editors tell me that online readers simply won’t finish longer articles. With today’s technologies, reading is simply more of a chore than it’s been in the past. Access to reading material is amazingly easy — a revolution, in fact — but reading is more than just taking in information, and the aesthetics of text presentation involves more than just making type pretty. It means making type functional as well.
Thanks to @petermeyers for the link.