Contextual advertising is a type of online advertising that serves ads to users based on the context of the website or content they are viewing. In other words, the ads that are displayed are relevant to the content or theme of the webpage or app.

Contextual advertising uses algorithms to analyze the content of a webpage or app and match it with relevant ads. This can be done by analyzing the words and phrases used on the page, the images and videos displayed, or other contextual cues. The goal of contextual advertising is to provide users with ads that are more relevant and interesting to them, which can increase the effectiveness of the ad campaign.

Contextual advertising is often used in combination with other types of targeting, such as demographic or behavioral targeting, in order to reach specific audiences or segments. It is commonly used on websites, social media platforms, and mobile apps, and it is often used in conjunction with display advertising or search advertising.