Scroll events are actions that occur when a user scrolls through a webpage or application. These events can be detected by programming languages like JavaScript, allowing developers to create interactive features that respond to user scrolling. For example, a website might change the appearance of a header or load new content as the user scrolls down the page. In web development, scroll events can enhance user experience by providing visual feedback or triggering animations. They can also be used for performance optimizations, such as lazy loading images or infinite scrolling, where new content is automatically loaded as the user reaches the bottom of the page.