As a web developer you have to balance how flash your site is going to be and how useable it is going to be to disabled people. Blind people are disabled, so when they surf the web, navigational and content hints that are hidden in the colour and layout is completely missed.
More importantly, these blind users often use a different computer setup which is very different. Some people use screen readers (e.g. Jaws) and some people use "basic" web browsers like Lynx or Links. These web browsers usually ignore all the added sugar to web pages and drills down straight to the content.
One of Internets most busy surfers is Google and who want's to reject Google access to your web page which would reduce your web page's chances of being found.
Conclusion is simple. Do not ignore blind web users. Google is one of them and that's a friend you don't want to reject access.