An ad network is a platform that connects advertisers with publishers who want to display ads on their websites or apps. It acts as an intermediary, helping advertisers reach their target audience while providing publishers with a way to monetize their content. Ad networks aggregate ad inventory from various publishers and sell it to advertisers, often using data to optimize ad placements. These networks can offer different types of ads, such as display ads, video ads, or mobile ads. By using an ad network, advertisers can efficiently manage their campaigns and track performance, while publishers benefit from increased revenue opportunities without needing to negotiate directly with each advertiser.