An ad exchange is a digital marketplace where advertising inventory is bought and sold, often through automated auctions.
How it works in retail
Publishers make ad opportunities available, while advertisers or their platforms evaluate and bid on them. An exchange may support open auctions or restricted trading arrangements.
A retail example
A fashion advertiser bids for a display placement when an eligible visitor loads a publisher’s page.
What to keep in mind
An exchange is distinct from the advertiser’s buying platform and the publisher’s selling platform. Auction access alone does not ensure relevant audiences or effective campaigns.
How an advertising opportunity is traded
In a typical auction-based transaction, a publisher makes an ad opportunity available, buying platforms evaluate the available information, and eligible buyers submit bids. The selection process applies the relevant auction rules and publisher requirements. The selected advertisement can then be served in the available placement. The exact sequence and commercial arrangements differ by system.
Exchange, buying platform and ad network
A demand-side platform is a tool advertisers use to manage buying. A supply-side platform helps publishers manage and offer inventory. An ad exchange connects buying and selling opportunities. An ad network commonly packages inventory for advertisers. One company may provide more than one of these functions, so the business name alone does not describe its role in a transaction.
What a retail marketer should compare
Consider inventory quality, placement transparency, audience relevance, fees and measurement. Winning an auction establishes that an ad opportunity was bought; it does not establish that a shopper noticed the ad or that the advertising caused a purchase.
Sources & further reading
Google Ad Manager: Open Bidding
Examples are illustrative. Terminology and measurement conventions can vary by business and market.