Some visitors won’t have updated to the latest version of their browsers either. Again they might not be able to see anything on your website.
The way round this is to ensure your business website is as standards compliant as possible. This way the site will be both backwards and forwards compatible. Older browsers might not be able to see everything modern and snazzy on your site, but an older browser will be able to display the most important thing on your business web site, the basic content about your company.
All the websites built here at Toolkit Websites by our webdesigners have been checked to ensure they display correctly on as many browsers as possible.
Avoid having an all flash site as older browsers, and alternative browsers such as screen readers may not be able to display your lovingly crafted animations.
A good way to check how your website appears in a range of browsers is to use a service like Browsershots (http://browsershots.org/) or Browsercam (http://www.browsercam.com)