A "Must Read" for anyone doing anything on the Internet and/or using emails to communicate with the public. It does not matter if you do not sell anything. It also does not matter if you only give advice or free information. It only matters that people are able to find your website, publication, information or whatever it is that you display, or make available to the public.
ADA Compliance is something that should be done by a properly trained and experienced person, preferably a lawyer. I strongly advise that you do not DIY, especially the first time for each different relevant item or issue. If, for example, you have a website or product, which was approved by a lawyer and the website/product etc is of a static nature, you could probably think about DIY, if any changes are being considered.