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.
UPDATE: Since writing this post in August 2017, several important changes have taken place in the laws regarding ADA compliance for websites. On December 26, 2017, the Department of Justice announced that they have withdrawn the Obama-era Advance Notice of Proposed Rulemaking mentioned in this article which intended to require ADA website compliance. The DOJ’s withdrawal announcement stated, “The Department will continue to assess whether specific technical standards are necessary and appropriate to assist covered entities with complying with the ADA.”
This is the exact opposite of mistake #1. Let me start by revealing a dirty little secret when it comes to website design. Most people think, Oh, I’m going to hire a professional website firm because I want a “real website” As opposed to a Word Press website or something else. And what most people don't realize is that all websites are made from the same stuff.
For most people, the Americans with Disabilities Act (ADA) conjures up pictures of physical accommodations such as wheelchair ramps near building entrances, handicapped parking spaces, and the use of braille writing on signs and placards. These measures have been tremendously valuable in helping the 56.7 million Americans with a disability function and thrive within society.
The ADA defines a covered disability as a physical or mental impairment that substantially limits one or more major life activities, a history of having such an impairment, or being regarded as having such an impairment. The Equal Employment Opportunity Commission (EEOC) was charged with interpreting the 1990 law with regard to discrimination in employment. The EEOC developed regulations limiting an individual's impairment to one that "severely or significantly restricts" a major life activity. The ADAAA directed the EEOC to amend its regulations and replace "severely or significantly" with "substantially limits", a more lenient standard.
Most recently, however, pizza chain Domino's has been brought under suit for their website not being accessible for specialty ordering. The U.S. Supreme Court refused to review the case, instead upholding the decision of the 9th U.S. Circuit Court of Appeals who said the “alleged inaccessibility of Domino’s website and app impedes access to the goods and services of its physical pizza franchises—which are places of public accommodation.”