Glossary » diversity
things vary more than you’d ever expect. Users vary by preferences, skills, impairments, interests, language, and culture. Computers vary by operating system, processor speed, screen size, memory, and networking abilities.
Design for diversity, or expect to succeed with only a very narrow market.
Design for universal access: provide for interoperability with many applications; provide accessibility to the disabled; provide customization and localization features for people from different countries and backgrounds.