Usability and accessibility are central to good web design… and yet both are frequently ignored, or at least are not given the weighting they warrant when it comes to making design decisions. They are about making sure that your site content can be accessed by the widest possible audience, and delivering the information and functionality users want in a way they’re comfortable and familiar with.
Usability The theory behind web usability is straightforward enough: simple, elegant and functional design helps users to achieve what they want to achieve online more effectively. It’s about taking the frustration out of the user experience, making sure things work intuitively, eliminating barriers so that users accomplish their goals almost effortlessly.
Your goal is to help the user to do what they want to do in the most efficient and effective way possible. Everything else is just web clutter. Achieving a simple, elegant design that delivers what the user wants with a minimum of fuss isn’t easy, but putting in the effort can pay huge dividends.
If your site complies with accessibility guidelines it will also work seamlessly with hardware and software designed to make the internet more accessible to people with disabilities. For example, by making sure you include descriptive text alternatives to images and multimedia content on your website you can help visually impaired or even completely sightless visitors to access your site through special text-to-speech software and/or text-to-Braille hardware.
How stringently you choose to adhere to these accessibility guidelines will depend on several factors, including the nature of your site, your target audience and, in some circumstances, the requirements of local accessibility legislation