In addition, a sizable percentage of the population is physically challenged or has related problems. Making your page accessible means bearing in mind that not all of the visitors to your web site will be viewing it on a monitor and navigating with a mouse. Some will be having your page read to them by a speech synthesizer. Others will be using a Braille reader. Some people may be using a specialized input device or keyboard.
Some folks just have trouble reading and get distracted easily.
Some are color-impaired. A clear, well-formatted site, with easy words, can make it easier on everyone. If you must have a site with ants crawling across a screen and the words falling out of hot air balloons, then learn how to provide textual equivalent for any non accessible content. Most of their guidelines are easy to implement, without detracting from the general style and look of your page. I have made some tools to help you get the look you want while increasing your site's accessibility.