Well, I think the windowing system is to blame. It is vertical space that is precious but your eyes can't find too much use for horizontal space. Think pages of

Well, I think the windowing system is to blame. It is vertical space that is precious but your eyes can't find too much use for horizontal space. Think pages of a newspaper that is divided into nice columns and compartments for a good reason. So, there's extra horizontal space on your wall-sized monitor and a good windowing system supports the user in maximizing its usage and not necessarily in maximizing each window. However, systems like Windows make it near impossible to make your windows behave. A typical scenario is having a couple of browser windows open for reading (like having some reference documentation at hand) and simultaneously typing into an active Emacs window partially/mostly underneath them both. If the windowing system insists on popping the active window to the top any of this becomes impossible, and you pretty much have no choice but to fall back to merely flipping between windows, and at this point it begins to feel stupid not to maximize all of them anyway. But the downside is there, too. Going back to books and newspapers for a reference, in opposition web pages can be just horrible to read when the browser window is maximized. You don't read a book in a widescreen aspect ratio either. Your eyes beg for a limited visual region to operate in. As for myself, I've found that I get a nice reading width by stretching the width of the browser window to 2/3 or 3/5 of the width of the screen. If ads are cluttering the sides or the layout flows outside then Readability takes care of it. As for design advice, "p { width: 66em !important }" would be good.