The Department of Justice’s revised regulations for Titles II and III of the Americans with Disabilities Act of 1990 (ADA) were published in the Federal Register on September 15, 2010. These regulations adopted revised, enforceable accessibility standards called the 2010 ADA Standards for Accessible Design, "2010 Standards." On March 15, 2012, compliance with the 2010 Standards was required for new construction and alterations under Titles II and III. March 15, 2012, is also the compliance date for using the 2010 Standards for program accessibility and barrier removal.

Yes, in time non-ADA compliant websites will be penalized in the search engines. It's already on their radar. But for now they are still negatively affected, just in an indirect way. Live traffic behavior (user experience) is now factored into Google's algorithm and is a ranking signal. Negative user interactions absolutely have negative affects on rankings.
Yes, all websites must have hand rails in the rest rooms, ramps in lieu of front porch stairs and elevators with doors wide enough for wheelchairs to be easily loaded into them. Seriously though, ADA only covers Americans, and the Internet is hardly just an American institution. Besides, browsers can already be configured to override the web designer’s pre-configured fonts, font sizes, font and page and page background colors, etc, to make it much easier to read. Also, the big 3 Operating Systems (MS Windows, MAC, and Linux) have text-to-speech programs which will allow the computer to read...
The gray area is a matter of scale and purpose. If you have a small business which serves as specific market it's a good idea to make the site as user and disability friendly as possible. If, however, your market serves segments with a likeliness to have various handicaps or disabilities you should address that with an ADA Compliance review of the site. Also consider the scale and purpose of an organization. Publicly traded large businesses need to concern themselves more than a single location family owned retailer and if someone sues your flower shop because the text was too small or didn't have "image alt tags" causing them distress... That's pretty frivolous and would likely not stand.
Yes, as of 2018 websites absolutely must be ADA compliant.  Its a new but very scary issue that has flared up over the last year and is set to cause a LOT of turmoil.  The Supreme court issued a judgement that opened up a loophole and opportunity-chasing lawyers are aggressively soliciting handicapped people and convincing them to sue unsuspecting website owners (pretty much every website owner on the planet, as not a single one of us were ADA compliant before now.)

I own a medical practice in California with 5 employees. Since I have under 15 employees am I exempt from needing to have my website comply with the ADA? I know that my physical practice is exempt from ADA policies regarding employment (under 15) but I don’t know if that extends to websites. My website is not an important part of my practice and I don’t really want to sink any funds into it if I don’t need to.
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. 
Many web developers have already realized this too and are exploiting business owners for $3k-$20k to make their sites compliant because they have no choice.  So we came up with an extremely low-cost solution so everyone can remove themselves from risk, have compliant websites, and immediately.  My website is compliant.  Visit it, press the handicap widget at the top, and play with its simple functions.  We can custom build and install one for anyone's website that's reading this.  It will deliver all the same functions, and we'll code it into your site for you so you don't have to worry about this risk any longer.  Everybody needs this.  Feel free to contact me for details if interested.
The truth is, when you’re assembling like a furniture, you’re not a professional furniture builder, and therefore the quality and the output is not going to be as good. And that metaphor applies to website design. Most people are not professional digital marketers or designers or understand user personas, or how to get traffic, or any of those things. And so, not only are you using all of your time to build the website but then you’re not getting as high-quality an output as you would as if you just hired someone who did that full time.
I was educated at the Illinois Institute of Art in Chicago and have over decade of graphic design experience developing t-shirts, posters, flyers, illustrations, web graphics, and many more. All of my work delivers on creating high quality images filled with detail and color. My belief in establishing a good relationship as well as excellent communication with each of my clients helps me produce the professional work they are looking for. My ambitious nature and need to create fuels my drive to always deliver the best for my clients.
Thanks for writing. While I’m not a lawyer I believe if your physical practice is ADA exempt your web presence, as an extension of that physical business would maintain the same exemption status. If you’d like to be absolutely certain I’d confer with an ADA lawyer (email us, questions at yokoco dot com if you need a referral) but I don’t believe you have reason to worry.
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.

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 one of the most complicated pieces of legislation in the sphere of accessibility. Let’s look at some of the ins and outs of what an ADA compliant website means today.
The way a lot of people think about getting a new website is, they have a certain amount of money and they think, If I pay less money for a website, I'll have extra money left over, therefore I win. And so they'll go and get a Square Space or a Wix or a Go Daddy website, and they'll think because they've saved money they're coming out ahead of the deal.
The Americans with Disabilities Act (ADA) was first passed in 1990. Twenty years later, the US Department of Justice released an update called the 2010 ADA Standards for Accessible Design. These standards cover the design of physical spaces and have been interpreted to include web locations as well, so it can be difficult for the would-be accessible website designer to use them.
For instance, if you have a video that displays the benefits of your product, but it doesn’t have captions, then people who are deaf or hard of hearing will not get to find out how great your product is. The same goes for when you have images with no alternate text. The point of the alternate text is to allow screen reading tools to describe the image to someone who is blind, so if you don’t have that text, some of your audience will miss out. Similarly, it’s important to ensure your website is fully accessible without a mouse so that people with physical limitations can use it.
You are correct, ADA defines an “employer” as any person who is 1) engaged in an industry affecting commerce; 2) employes 15 or more full-time employees each work day; and 3) for at least 20 or more calendar weeks in the year. In the context of physical spaces, ADA would not apply to companies with fewer than 15 employees. However, courts don’t seem to have come to a consensus on what digital compliance really should look like. Because websites can be accessed anywhere in the country, small business owners might potentially face lawsuits in unfavorable jurisdictions. If you are a small business owner, I would recommend consulting with an accessibility lawyer and ask what they recommend.