An anchor ad is a type of online advertising that is displayed in a fixed position on a website or web page. The ad is "anchored" to a specific location on the page and remains visible even as the user scrolls down the page or navigates to different parts of the site. This allows the ad to remain prominent and in the user's field of view, increasing the chances that the user will notice and engage with it. Anchor ads are often used for branding and awareness campaigns, and can be effective at driving traffic and engagement to a website or landing page.