Mobile usability refers to the ease with which users can navigate and interact with a website on mobile devices such as smartphones and tablets. Websites that are not optimized for mobile usability may experience issues such as small text, unplayable content, or tap targets that are too close together, making it difficult for users to access and engage with the content. Mobile usability is an important ranking factor for search engines like Google, especially since the majority of internet traffic now comes from mobile devices. Websites that provide a poor mobile experience may be penalized in mobile search results or have difficulty ranking competitively. To address mobile usability problems, webmasters should adopt responsive web design principles, optimize page loading speed, and ensure that content is easily accessible and readable on mobile devices. They can also use tools like Google's Mobile-Friendly Test to identify and fix mobile usability issues on their website.