Web Accessibility is a term coined to express the things that are done for ensuring the access to the features and content of a website. Web accessibility and Search Engine Optimization are interrelated in many ways. Content which are readable by the users and the SEO optimized content are both readable by Search Engines. Screen Readers which are used for accessing information by people with disabilities are relying on the structure of the content and semantics for the users.
Search Engines crawl content and index them in their database and shows the content depending upon relevancy when asked by users. Web Accessibility guidelines help website designers and developers to implement specific structure and codes for making the content visible to the user. In earlier days SEO dependent more on black hat methods link link building techniques. But as years passed SEO got aligned with Accessibility and the more accessible sites have become more SEO friendly.
The following are some of the general tips for increasing web accessibility and SEO factors