Parallax scrolling is a web design technique that creates an illusion of depth by moving background images at a different speed than foreground images. This effect enhances the visual experience, making websites more engaging and interactive. As users scroll down a page, they perceive layers of content that appear to move independently, creating a sense of immersion. This technique is commonly used in video games and mobile applications to add dynamism to the user interface. By incorporating parallax scrolling, designers can guide users' attention and improve storytelling, making the overall experience more enjoyable and memorable.