Web Accessibility?

conJunk asks: "With Slashdot recently becoming HTML 4.01 compliant, my thoughts now drift to the subject of web accessibility. We all know that the Section 508 requirements are legally binding to those who work for or with the U.S. government, but it's still unclear whether or not U.S. companies are required to have accessible sites (unlike England, where it's very clear). How important are web accessibility and the W3C Accessibility Guidelines to you and/or your company? Where do you see this issue going in the next 10 years?"