Forum Moderators: phranque
[webaim.org ]
If you actually provide content to the US government, some state governments, or any entity dealing with same you may wish to consult a lawyer to ensure compliance.
Otherwise read and decide what is viable. Accessibility will become more rather than less important as time goes by. In a virtual world you can not see a person who can not get in your place of business so may not know what business (and profit) you are losing. I follow the w3c accessibility guidelines as much as possible simply as as a dollars and cents proposition.