Handicap Accessible Optimization Opens Markets

The blind population is greatly influenced by word-of-mouth advertising. When blind consumers hear about a good, easily accessible (to them) site, they will pass it on to a few hundred people on one listserv, and somebody else will pass it on to another. That could turn into thousands of people visiting your website. And given their significant transportation problems, blind consumers are loyal to accessible sites. For disabled users, the Internet is freedom.
 
If your main goal is to expose your website to the greatest amount of people and have it understood by them, then the Accessibility Priority Checklist from the WAI (Link) will be of interest to you.