Usability and Accessibility
What's the difference between usability and accessibility?
Usability is generally defined as the ease with which a user can learn to operate, prepare inputs for, and interpret outputs of a system or component. Usability is what allows us to traverse though a web site, accessing information as easily as possible. In the short life of the Internet, numerous usability conventions and standards have been adopted to facilitate an efficient transfer of information.
Designing web content for a high degree of usability is widely recognized as an important, if not the most important, factor to take into consideration when developing web content.
Accessibility is usability that takes the disabled user into consideration. Accessible design requires that web content is translatable by the devices and technologies employed by the disabled.
A site may have good usability features for the general public but may be complete indecipherable to the disabled user. The converse, however, is not true. Typically, if a site is accessible to the disabled, it is highly usable to the general user, as well.
Experienced web developers already give usability a high priority in their work. It seems obvious that in order to be effective, a web site must be easy to use. Extending that ease of use to the disabled is the priority of developers of accessible web technology.