Since March 15, 2012, ADA compliance with the 2010 Standards will be required for new construction and alterations. In the period between September 15, 2010 and March 15, 2012, covered entities may choose between the 1991 Standards ADA Compliance (without the elevator exemption for Title II facilities), the Uniform Federal Accessibility Standards (Title II facilities only), and the 2010 Standards ADA Compliance.
This title outlines the administrative processes to be followed, including requirements for self-evaluation and planning; requirements for making reasonable modifications to policies, practices, and procedures where necessary to avoid discrimination; architectural barriers to be identified; and the need for effective communication with people with hearing, vision and speech disabilities. This title is regulated and enforced by the U.S. Department of Justice.
Decided by the US Supreme Court in 2002, this case [74][75] held that even requests for accommodation that might seem reasonable on their face, e.g., a transfer to a different position, can be rendered unreasonable because it would require a violation of the company's seniority system. While the court held that, in general, a violation of a seniority system renders an otherwise reasonable accommodation unreasonable, a plaintiff can present evidence that, despite the seniority system, the accommodation is reasonable in the specific case at hand, e.g., the plaintiff could offer evidence that the seniority system is so often disregarded that another exception wouldn't make a difference.

I know there may have been concerns that the ADA may be too vague or too costly, or may lead endlessly to litigation. But I want to reassure you right now that my administration and the United States Congress have carefully crafted this Act. We've all been determined to ensure that it gives flexibility, particularly in terms of the timetable of implementation; and we've been committed to containing the costs that may be incurred.... Let the shameful wall of exclusion finally come tumbling down.[41]

Level AA is a little more significant, and makes sites accessible to people with a wider range of disabilities, including the most common barriers to use. It won't impact the look and feel of the site as much as Level AAA compliance, though it does include guidance on color contrast and error identification. Most businesses should be aiming for Level AA conformity, and it appears to reflect the level of accessibility the DOJ expects. 
As organizations around the world scramble to bring their sites into compliance with the World Wide Web Consortium’s Web Content Accessibility Guidelines (WCAG), focus on other, preexisting accessibility regulations has also intensified. The United States’ Americans with Disabilities Act (ADA) is one of the most visible and complicated pieces of accessibility legislation. Let’s look at some of the ins and outs of what an ADA compliant website means today. Or, if you're interested in seeing the nitty-gritty details of your site's accessibility, request a free website audit report using the form on this page.
The Commission also recognizes that differences and disputes about ADA requirements may arise between employers and people with disabilities as a result of misunderstandings. Such disputes frequently can be resolved more effectively through informal negotiation or mediation procedures, rather than through the formal enforcement process of the ADA. Accordingly, EEOC will encourage efforts of employers and individuals with disabilities to settle such differences through alternative methods of dispute resolution, providing that such efforts do not deprive any individual of legal rights provided by the statute.
Technology is changing, and many website designers are using creative and innovative ways to present web-based materials. These changes may involve new and different access problems and solutions for people with disabilities. This Chapter discusses just a few of the most common ways in which websites can pose barriers to access for people with disabilities. By using the resources listed at the end of this Chapter, you can learn to identify and address other barriers.
While legal considerations might be your biggest worry, making your site more accessible is simply good customer service. More than 39 million Americans are blind and another 246 million have "low vision," Another one million are deaf in the U.S. Add to that people with mobility issues that prevent them from using their hands and that's a huge portion of the country's buying power.

...the full and equal enjoyment of the goods, services, facilities, or accommodations of any place of "public accommodation" by any person who owns, leases, or operates a place of public accommodation. Public accommodations include most places of lodging (such as inns and hotels), recreation, transportation, education, and dining, along with stores, care providers, and places of public displays.
Webpage designers often have aesthetic preferences and may want everyone to see their webpages in exactly the same color, size and layout. But because of their disability, many people with low vision do not see webpages the same as other people. Some see only small portions of a computer display at one time. Others cannot see text or images that are too small. Still others can only see website content if it appears in specific colors. For these reasons, many people with low vision use specific color and font settings when they access the Internet – settings that are often very different from those most people use. For example, many people with low vision need to use high contrast settings, such as bold white or yellow letters on a black background. Others need just the opposite – bold black text on a white or yellow background. And, many must use softer, more subtle color combinations.
The final title contains a variety of provisions relating to the ADA as a whole, including its relationship to other laws, state immunity, its impact on insurance providers and benefits, prohibition against retaliation and coercion, illegal use of drugs, and attorney’s fees.  This title also provides a list of certain conditions that are not to be considered as disabilities.
So, what do I mean by that? That sounds weird. So, when I say designer, I mean someone who's strictly an artist, and there's a lot of those out there. A lot of 'designers' are only concerned about the aesthetics of the site. What it looks like, or if its unique, or if it follows the latest website design trends. But at the end of the day they don't really 'get it' when it comes to what the primary purpose of a website is.