What is the primary purpose of an ad exchange?

The primary purpose of an ad exchange is to facilitate the buying and selling of digital ad inventory. This is achieved by providing a platform where publishers can offer their available ad space and advertisers can bid in real time to purchase that space. Ad exchanges enable a more efficient transaction process by automating the auctioning of ads, allowing a wide range of advertisers to access diverse inventory across different digital properties. This system benefits both parties: publishers maximize their revenue potential by reaching multiple advertisers, while advertisers gain access to a broad range of inventory options tailored to their target audiences.

In contrast, the other options focus on different aspects of digital marketing. Hosting video content is a function typically associated with video hosting platforms, not ad exchanges. Creating SEO-friendly content pertains to content marketing strategies rather than the transactional nature of ad exchanges. Measuring brand awareness metrics involves analytics tools that assess the effectiveness of marketing campaigns, which is a separate function from the buying and selling of ad inventory. Thus, option B distinctly captures the core functionality of ad exchanges in the digital advertising ecosystem.