Until the ADA is updated to address the special case of website accessibility, or the Department of Justice releases its website accessibility regulations, complying with WCAG 2.0 Level AA is the best way to ensure that people with disabilities have equal access to your website. The overview below is a great starting point about meeting the WCAG 2.0 Level AA recommendations.
When collecting feedback, ask users what type of adaptive technologies they use. This will allow you to cater your website to your particular clientele, and will help you appoint resources toward the best compliance options. Navigating the Internet is particularly challenging for people with limited or no vision. Many blind people use specialized web browsers and software that works with standard web browsers, like Internet Explorer, that have features that enable users to maximize their Internet use and experience. This screen reading software reads the HTML code for websites, and gives the user a verbal translation of what is on screen.
Prohibited discrimination may include, among other things, firing or refusing to hire someone based on a real or perceived disability, segregation, and harassment based on a disability. Covered entities are also required to provide reasonable accommodations to job applicants and employees with disabilities.[16] A reasonable accommodation is a change in the way things are typically done that the person needs because of a disability, and can include, among other things, special equipment that allows the person to perform the job, scheduling changes, and changes to the way work assignments are chosen or communicated.[17] An employer is not required to provide an accommodation that would involve undue hardship (significant difficulty or expense), and the individual who receives the accommodation must still perform the essential functions of the job and meet the normal performance requirements. An employee or applicant who currently engages in the illegal use of drugs is not considered qualified when a covered entity takes adverse action based on such use.[18]
This particular lawsuit amounted to nothing more than a shakedown for cash, as the current laws would make it difficult to win the suit in court (more about this later) but it prompted me to dive deeper into the issue of ADA compliance. Through my research, I discovered there are some new laws on the horizon that could make ADA compliance mandatory, which means web designers and digital marketers need to know how to prepare.
The World Wide Web Consortium (W3C) established the main international standards and accessibility for the World Wide Web. The WCAG is created by the W3C to provide a standard for web content accessibility that can be shared around the world. The WCAG is meant to accompany organizations as a sort of blueprint on how to make their websites ADA compliant.
Courts have taken essentially the following position on the issue of whether websites are places of public accommodation: Website accessibility fulfills the spirit of the ADA by lowering the barriers for people with disabilities to participate in business and commerce. As such, commercial websites need to comply with ADA regulations. Judges have reached this conclusion in several high-profile cases, such as the National Federation of the Blind’s lawsuit against the Scribd digital library. As a result of this case, Scribd agreed to redesign its website to work with screen reader software by the end of 2017.
This was a case filed before The United States District Court for the Eastern District of Michigan Southern Division on behalf of the Michigan Paralyzed Veterans of America against University of Michigan – Michigan Stadium claiming that Michigan Stadium violated the Americans with Disabilities Act in its $226-million renovation by failing to add enough seats for disabled fans or accommodate the needs for disabled restrooms, concessions and parking. Additionally, the distribution of the accessible seating was at issue, with nearly all the seats being provided in the end-zone areas. The U.S. Department of Justice assisted in the suit filed by attorney Richard Bernstein of The Law Offices of Sam Bernstein in Farmington Hills, Michigan, which was settled in March 2008.[66] The settlement required the stadium to add 329 wheelchair seats throughout the stadium by 2010, and an additional 135 accessible seats in clubhouses to go along with the existing 88 wheelchair seats. This case was significant because it set a precedent for the uniform distribution of accessible seating and gave the DOJ the opportunity to clarify previously unclear rules.[67] The agreement now is a blueprint for all stadiums and other public facilities regarding accessibility.[68]
The need to make websites, mobile apps, and other online properties accessible to all is only going to increase as time moves on. Smart business owners will do well to get in front of this issue and make sure that their websites are ADA compliant now so that all their customers have the equal access to the resources they offer. Not just because they want to avoid a lawsuit or government action, but because it’s the right thing to do.

This is the reason why I think web design firms have to position themselves as solution providers and not just web guys/gals. A client doesn't need a website, they need sales. The website is just part of that solution but it's not the solution and unlike web design, service like email marketing automation, SEO, and PPC requires an experienced professional.
The ADA provides explicit coverage for service animals.[22][23] Guidelines have been developed not only to protect persons with disabilities but also to indemnify businesses from damages related to granting access to service animals on their premises. Businesses are allowed to ask if the animal is a service animal and ask what tasks it is trained to perform, but they are not allowed to ask the service animal to perform the task nor ask for a special ID of the animal. They cannot ask what the person's disabilities are. A person with a disability cannot be removed from the premises unless either of two things happen: the animal is out of control and its owner cannot get it under control (e.g. a dog barking uncontrollably in a restaurant), or the animal is a direct threat to people's health and safety. Allergies and fear of animals would not be considered a threat to people's health and safety, so it would not be a valid reason to deny access to people with service animals. Businesses that prepare or serve food must allow service animals and their owners on the premises even if state or local health laws otherwise prohibit animals on the premises. In this case, businesses that prepare or serve food are not required to provide care or food for service animals, nor do they have to provide a designated area for the service animal to relieve itself. Lastly, people that require service dogs cannot be charged an extra fee for their service dog or be treated unfairly, for example, being isolated from people at a restaurant. People with disabilities cannot be treated as "less than" other customers. However, if a business normally charges for damages caused by the person to property, the customer with a disability will be charged for his/her service animal's damages to the property.

The Federal Communications Commission (FCC) enforces regulations covering telecommunication services. Title IV of the ADA covers telephone and television access for people with hearing and speech disabilities. It requires telephone and Internet companies to provide a nationwide system of telecommunications relay services that allow people with hearing and speech disabilities to communicate over the telephone.

This title prohibits private places of public accommodation from discriminating against individuals with disabilities. Examples of public accommodations include privately-owned, leased or operated facilities like hotels, restaurants, retail merchants, doctor’s offices, golf courses, private schools, day care centers, health clubs, sports stadiums, movie theaters, and so on.  This title sets the minimum standards for accessibility for alterations and new construction of facilities. It also requires public accommodations to remove barriers in existing buildings where it is easy to do so without much difficulty or expense.  This title directs businesses to make "reasonable modifications" to their usual ways of doing things when serving people with disabilities. It also requires that they take steps necessary to communicate effectively with customers with vision, hearing, and speech disabilities.  This title is regulated and enforced by the U.S. Department of Justice. 
Once you have been hired and started work, your employer cannot require that you take a medical examination or ask questions about your disability unless they are related to your job and necessary for the conduct of your employer's business. Your employer may conduct voluntary medical examinations that are part of an employee health program, and may provide medical information required by State workers' compensation laws to the agencies that administer such laws.
On September 25, 2008, President George W. Bush signed the ADA Amendments Act of 2008 (ADAAA) into law. The amendment broadened the definition of "disability", thereby extending the ADA's protections to a greater number of people.[43] The ADAAA also added to the ADA examples of "major life activities" including, but not limited to, "caring for oneself, performing manual tasks, seeing, hearing, eating, sleeping, walking, standing, lifting, bending, speaking, breathing, learning, reading, concentrating, thinking, communicating, and working" as well as the operation of several specified major bodily functions.[43] The act overturned a 1999 US Supreme Court case that held that an employee was not disabled if the impairment could be corrected by mitigating measures; it specifically provides that such impairment must be determined without considering such ameliorative measures. It also overturned the court restriction that an impairment which substantially limits one major life activity must also limit others to be considered a disability.[43] In 2008, the United States House Committee on Education and Labor stated that the amendment "makes it absolutely clear that the ADA is intended to provide broad coverage to protect anyone who faces discrimination on the basis of disability."[44] Thus the ADAAA led to broader coverage of impaired employees.
There have been some notable cases regarding the ADA. For example, two major hotel room marketers (Expedia.com and Hotels.com) with their business presence on the Internet were sued because its customers with disabilities could not reserve hotel rooms, through their websites without substantial extra efforts that persons without disabilities were not required to perform.[58] These represent a major potential expansion of the ADA in that this, and other similar suits (known as "bricks vs. clicks"), seeks to expand the ADA's authority to cyberspace, where entities may not have actual physical facilities that are required to comply.
A. The ADA permits an employer to refuse to hire an individual if she poses a direct threat to the health or safety of herself or others. A direct threat means a significant risk of substantial harm. The determination that there is a direct threat must be based on objective, factual evidence regarding an individual's present ability to perform essential functions of a job. An employer cannot refuse to hire you because of a slightly increased risk or because of fears that there might be a significant risk sometime in the future. The employer must also consider whether a risk can be eliminated or reduced to an acceptable level with a reasonable accommodation.
The ADA itself holds different organizations to more/less stringent standards based on a host of factors, government funding being a major one. Government agencies themselves are usually held to the most severe standards. That said, while ADA has adopted WCAG as the defacto standard, from what I’ve seen it appears they’re going with AA compliance as the most reliable one. That said, we’ve done work with some organizations who’ve chosen to comply with AAA in an effort to be as buttoned up as possible from an accessibility and experiential perspective. We’ve also worked with some who have tighter budgers and aim for level A compliance and have a more “react and repair” mindset when they discover anything in their site that is giving someone hardship from an accessibilirt standpoint.