Depending on which statistics you believe there are 10-28% of the U.S. population that have some sort of impairment that makes using the Internet more difficult than for those who are not impaired. These impairments are classified by type.
- Visually Impaired - While most people think "no vision" this category includes those who use corrective lenses, as well as those who are color blind.
- Hearing Impaired - With the exception of multimedia most hearing impaired are not impaired in their use of the internet.
- Mobility Impaired - Ranging from people moderate impairment such as arthritis to quadriplegics who use mouth sticks, "puff and sip" devices.
- Cognitive Impairment - Down's Syndrome is a classic example in this category but there are many others who fall in this category that are not so obvious. A person with dyslexia or other learning disability for example may have difficulty with many sites that would not affect someone with another type of impairment.
- Seizure Disorders - Screen flickers with in the range of 2 Hz to 55 Hz can cause people with seizure disorders such as epilepsy to have a seizure. This is not a problem for most websites but there have been some animated advertisements that have caused seizures.
In addition to the groups identified above the general web population benefits from accessible sites since accessible sites benefit those without disabilities as well.
- Increase Market Share - If you site is more accessible than that of your competition those who benefit from accessibility will prefer to do business with you.
- Increase Site Usability - When a site is designed with accessibility in mind care is give to site structure, navigation and content that generally results in a more usable site for all visitors.
- Decrease Maintenance Cost - Sites written to accessibility standards incorporate features such as separation of content from presentation that makes additions and changes to the site less expensive than sites written with "tag soup" and sniffing for browser specific solutions.
- Search Engine Friendly - Sites that are written to standards us proper mark-up and include relevant descriptions in alt and title tags can result in higher search engine ranking than sites that do not use appropriate mark-up and alt tags.
- Preferred Vendor Status - If you do business with the U.S. government agencies or state agencies there are regulations that require those entities to purchase from those business who comply with §508 over those who do not.
- Avoidance of Legal Liability - I have been unable to find any private business held liable under anti-discrimination laws for not having an accessible site but there have been suits filed alleging discrimination based on sites not being accessible.
- Examples include:
- August 2004:,State of New York enforces ADA against travel sites - Priceline.com and Ramada.com have agreed to changes that will allow users with "screen reader software" and other technology to navigate and listen to the text throughout their Web sites, according to New York Attorney General Eliot Spitzer.
- July 2003: When the Americans With Disabilities Act Goes Online - Application of the ADA to the Internet and the Worldwide Web Position Paper by the National Council on Disability
- July 2000: AOL & American Federation for the Blind - The American Federation for the Blind filed suit on behalf of visually impaired people who could not use AOL, which was the largest provider of internet services at the time. The suit was filed because AOL's proprietary browser was incompatible with screen readers . The suit was settled by AOL agreeing to make their browser compatible with screen readers.
- June 1999: Maguire vs. Sydney Organizing Committee for the Olympics - Bruce Maguire filed suit against the Sydney Olympic Committee because the website for the 2000 Olympics was not usable by the blind. They were unable to "see" the schedule for individual events, order tickets or view results because the site was missing any accessibility features including such simple accommodations as alt tags and accessible table mark-up.
- Examples include: