Web designers are just adopting what we've learned over the past 500 years since the printing press about page layout and what is easy to read. For example, most good Web sites put any long blocks of text in black letters on a white background, to approximate the high contrast of black ink on paper. But the Web is not a book, nor is it a piece of paper. Recent research indicates that blocks of text that make a book easy to read are hard to read on the Web. And bullet points, which are used occasionally in books, are far more prevalent in Web sites.
People tend to use the Web to find information rather than to settle in for a long read.
Moreover, The Web also affords a few new navigation features that are missing in books. Clickable links and electronic searches can make finding related information easier and faster than in print media. Color, animation, video, and sound are cheaper and easier to deliver via the Web than in print. Filmmakers just pointed their camera at the proscenium and captured the action. So it is with the Web today.