Ad exchange
An ad exchange is an online platform for buying and selling advertising inventory across websites, mobile sites, and mobile apps. Think of it like a digital marketplace, where the deals take place automatically and in real-time.
Ad exchanges play a key role in the world of programmatic advertising, which automates the bidding process for digital ad space. They connect the supply side — parties with ad space to sell, including publishers (website or app owners) and advertising networks (more on these below) — with the demand side (advertisers or agencies wanting to place ads).