In an August 2016 case involving the University of California Berkeley, the DOJ ruled that the public university was in violation of ADA Title II (similar to Title III but it instead applies to government organizations) because their YouTube channel’s videos didn’t include captions for hearing impaired visitors. The DOJ found this to violate the ADA as deaf users did not have equal access to the online content.
The 2014 case involving Peapod, an online grocery retailer emphasizes that being ADA compliant goes beyond your website. The settlement required Peapod to make its mobile applications accessible by March 2015 and its website accessible by September 2015. Since mobile apps are fast becoming the preferred method of online shopping, e-commerce sites must focus on app accessibility too. 
Error prevention on important forms (3.3.4): For pages that create legal commitments or financial transactions or any other important data submissions, one of the following is true: 1) submissions are reversible, 2) the user has an opportunity to correct errors, and 3) confirmation is available that allows an opportunity to review and correct before submission.
State and local governments will often post documents on their websites using Portable Document Format (PDF). But PDF documents, or those in other image based formats, are often not accessible to blind people who use screen readers and people with low vision who use text enlargement programs or different color and font settings to read computer displays.

This past September marked the first time a judge ruled that the ADA applies even to businesses without a physical location. Scribd, an e-book subscription service is considered to provide "a place of public accommodation." Their services are not accessible to blind persons because they cannot be read with a screen reader. The judge reasoned, "Now that the Internet plays such a critical role in the personal and professional lives of Americans, excluding disabled persons from access to covered entities that use it as their principal means of reaching the public would defeat the purpose of this important civil rights legislation."
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.

Poorly designed websites can create unnecessary barriers for people with disabilities, just as poorly designed buildings prevent some people with disabilities from entering. Access problems often occur because website designers mistakenly assume that everyone sees and accesses a webpage in the same way. This mistaken assumption can frustrate assistive technologies and their users. Accessible website design recognizes these differences and does not require people to see, hear, or use a standard mouse in order to access the information and services provided.

While some might be tempted to do this if you understand anything about how Google indexes websites, someone who has thousands of pages on their site would lose rankings. The price of making your site fully accessible depends on how large your website is. Making the best decision for your specific situation is best done by consulting a professional.
That carousel or image slider on your site looks beautiful. That stunning video on autoplay may have cost thousands to produce. Users with cognitive limitations, however, may not comprehend your information quickly enough before the view changes or your video ends. Other users may want to start over, or go back and review something they saw or heard.
In a society in which business is increasingly conducted online, excluding businesses that sell services through the Internet from the ADA would ‘run afoul of the purposes of the ADA’” in that it would prevent “‘individuals with disabilities [from] fully enjoy[ing] the goods, services, privileges, and advantages, available indiscriminately to other members of the general public.
Further complicating the issue, the U.S. recently appeared to be on the verge of adopting more comprehensive accessibility requirements. Federal regulations slated to go into effect in January 2018 would have held federal websites to the standards of WCAG 2.0 Level AA, the set of guidelines that provide the basis for online accessibility rules for most of Europe and many other nations around the world. The current administration, however, has withdrawn this requirement as part of a general push toward deregulation, leaving the online applications of the ADA as murky as ever.

Upon discovering issues faced by disabled government employees and the public, revisions to section 508 were made. The issues that were uncovered involved websites, documents, and software programs. As of January 2018, the updated 508 standards require all federal agencies and contractors to create web content accessible to all. The updated standards also include Website 508 compliance.
The Americans with Disabilities Act (ADA) and, if the government entities receive federal funding, the Rehabilitation Act of 1973 generally require that state and local governments provide qualified individuals with disabilities equal access to their programs, services, or activities unless doing so would fundamentally alter the nature of their programs, services, or activities or would impose an undue burden.2 One way to help meet these requirements is to ensure that government websites have accessible features for people with disabilities, using the simple steps described in this document. An agency with an inaccessible website may also meet its legal obligations by providing an alternative accessible way for citizens to use the programs or services, such as a staffed telephone information line. These alternatives, however, are unlikely to provide an equal degree of access in terms of hours of operation and the range of options and programs available.
Courts have essentially taken three positions when approached with this issue. Some courts take the position that the ADA applies to all commercial sites because the law was meant to protect disabled individuals from having a more difficult time than able-bodied individuals from doing business. That is why the website Scribd was unable to get a case summarily dismissed and ended up settling.