A banner is a graphic image format used on the Internet as an advertising space with predefined, standardized dimensions. It is one of the earliest and most basic visual elements of display advertising. Its main function is to attract the user’s attention and, through a click-through mechanism, redirect them to a target Internet address (URL) of the advertiser.
Conceptually, a banner functions as a digital billboard. It can be static (a still image) or animated (using formats such as GIF or HTML5), and its purpose is to convey a short and impactful advertising message. The effectiveness of banner advertising is mostly evaluated through the click-through rate (CTR), which shows how well the visual and text content has managed to engage the audience’s attention.
Although the effectiveness of traditional banners has decreased due to the so-called “banner blindness” (a phenomenon in which users ignore areas with ads), the banner format remains a staple in retargeting and programmatic ad buying, where it is used to maintain brand visibility.