This video from Ability Net explores the problems that keyboard users and screen reader users can face when attempting to navigate through an inaccessible website. Issues such as non-descriptive link titles, skipping over links, and no visual differentiation marking which link is currently selected can make navigation impossible for many users
Universal Design (UD) is an approach to design that increases the potential for developing a better quality of life for a wide range of individuals. It is a design process that enables and empowers a diverse population by improving human performance, health and wellness, and social participation (Steinfeld and Maisel, 2012). It creates products, systems, and environments to be as usable as possible by as many people as possible regardless of age, ability or situation.