When it comes to the Internet, if you’re willing, you can truly take the extra step of “universal design” in regard to accessibility by being aware of your visitors and their challenges. No matter what the site, the worst design flaw your Web site can have is remarkably relative to how much it impacts a single site visitor. And this is especially true in the case of accessibility.

Usability guru Jakob Nielsen notes on his usability site, “It's time we moved beyond technical accessibility when discussing how to improve the Web for users with disabilities. We should consider these users as users: As people who have jobs to perform and goals to accomplish when they use Web sites and intranets. Once we've achieved technical accessibility, our new goal must be task support and increased usability of Web sites and intranets for people with disabilities.”

Let’s take a look at the four main categories of disability types and how those categories affect Internet use and therefore Web site usability. Keep in mind that for each of these listings, there are certainly going to be some challenges or conditions that because of their severity, accessibility will not be completely successful.

The following disability categories are adapted from an excellent online resource and organization devoted to helping people and institutions overcome web accessibility issues. WebAim.org's main goal as cited on their site “is to improve accessibility to online learning opportunities for all people; in particular to improve accessibility for individuals with disabilities who currently may have a difficult time getting access to online learning opportunities.” It is a resource rich site and certainly one to bookmark for later information gathering. Here are their categories:

1.      Visual - blindness, low vision, color blindness.

2.      Hearing – mild loss, moderate loss, severe hearing loss and profound hearing loss. * Note: Remember with both of the above, there is a large spectrum as to the degree of the difficulty or loss in regard to the disability.

3.      Mobility or Motor Disabilities – inability to use mouse, slow response time, limited fine motor control. These are often disability issues caused by traumatic injuries such as loss of limb, or spinal cord injury, birth defects, diseases such as arthritis, Parkinson’s, and multiple sclerosis which all affect the user’s accessibility to the Web.

4.      Cognitive – learning disabilities, distractibility, inability to remember or focus on large amounts of information. These challenges are found in dyslexia, ADHD, brain injury and genetic diseases.

For more information on how to address each of these specific categories another excellent resource is The Web Content Accessibility Guidelines Vs. 2.0 an ongoing working Draft (July 30^th) published in full on-site by the W3C. The Web Content Accessibility Guidelines aims to define how to make Web content accessible to people with disabilities and define target levels of disability. The document outlines in detail design principles for creating accessible content.

The United Nations also addresses accessibility and lists further resources for study and direction on its page, Accessibility on the Internet. And take particular note of the University of Toronto’s University of Toronto's 10 HTML Commandments.