Pop-up ads are small windows that appear on a computer or mobile screen while browsing the internet. They often promote products, services, or websites and can be triggered by specific actions, such as clicking a link or visiting a page. These ads can be annoying for users, as they interrupt the browsing experience. Many web browsers and applications offer options to block pop-up ads, helping to create a smoother online experience. Despite their intrusive nature, some businesses use pop-up ads to capture attention and encourage users to sign up for newsletters or special offers related to their products or services.