Web standards are the formal standards and other technical specifications identified by the web community that define and describe aspects of the World Wide Web. In recent years, the term has been more frequently associated with a growing trend to ensure simple, affordable access to web technologies for all.
Why do I need to know about web standards?
Building with web standards benefits both site owners and users by increasing accessibilty for users (i.e. hearing impaired, those who use screen readers, et cetera), allowing a harmonious relationship with search engines, and enabling site developers to identify and make changes with ease and efficiency.