When I sit down to design a new website, I always take the user’s goals and needs into consideration. Actually, that’s an understatement. The website’s goals are to meet the user’s goals, and to do this you need take people’s needs and limits into consideration.
According to Chuck Upsdell  and his Browser News website, approximately 75% of all web users are browsing with their monitor resolution set to 1024×768 (SVGA) pixels or higher. At this high resolution, and with a browser window taking up the full screen, it is not uncommon for 25 words or more to be packed onto each line of text.
Many studies regarding line-length readability have been conducted, and with very few dissenting opinions, optimal readability and comprehension levels for the participants were found to lie at around 60 CPL (Characters Per Line) .
By having the main content section of your website resize with the browser window, you may be giving up control of your line-lengths, and therefore, your website’s text may become difficult to read when the browser window is maximized.
Measures for avoiding just such a situation have been architected into the CSS 2.0 specification, in the format of the designer specifying a ‘max-width’ or ‘min-width’ to an element with the goal of not letting the CPL get neither too high nor too low .
So what do we do? If you are purely interested in providing user-focused content wrapped in a user-centered design, then line-lengths and readability will be at the forefront of your decision list. Unfortunately (or fortunately) sites don’t work like that.
Large company websites usually have advertising, and those banners are designed to fit in a space X pixels wide by Y pixels tall, and no fluid layout should be allowed to break that (lest the owners plan to lose some advertising revenue).
Right now, I will be designing my websites with line-lengths and user readability in mind. Until someone shows me evidence to change my mind, that’s just the way it’s going to go down.
And oh yeah, Jakob Nielsen seems not to care about readability either — just look at how long those lines are… and the leading, my God, the leading!!!
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