In the US, it is if you're an incorporated business serving as a "public accommodation" as defined in the Americans with Disabilities Act, which includes hotels, restaurants, theaters, storefronts. If it is just your personal blog, it doesn't apply. It is the same law that requires storefronts to have wheelchair ramps, but not homes. See Gil v. Winn-Dixie:
https://scholar.google.com/scholar_case?case=674450226911160...