Ethan Marcotte is a web designer and developer known for his influential work in responsive web design. He popularized the concept through his 2010 article, which emphasized the importance of creating websites that adapt to various screen sizes and devices. This approach has since become a standard practice in web development. In addition to his writing, Marcotte has authored books and spoken at numerous conferences, sharing his expertise on web design and user experience. He has contributed to the broader conversation about web standards and accessibility, making significant impacts on how websites are built today.