The DoubleClick Ad Exchange is a real-time marketplace to buy and sell display advertising space.
By establishing an open marketplace where prices are set in a real-time auction, the Ad Exchange enables display ads and ad space
to be allocated much more efficiently and easily across the web. It’s just like a stock exchange, which enables stocks to be traded in
an open way.
Who participates in the Ad Exchange?
Again, imagine the Ad Exchange as a stock exchange. Only the largest brokerage houses actually plug into, say, the NYSE. In the Ad
Exchange world, those are:
•	 The large online publishers (sellers)—websites like portals, entertainment sites and news sites
•	 Ad networks and agency holding companies that operate networks (buyers)—companies that connect web sites with advertisers.
But it’s not just the direct participants who benefit. As an individual investor, you can buy and sell shares on the stock exchange
through an online broker, without needing to plug in to the NYSE mainframe. It’s the same for AdWords advertisers and AdSense
publishers who get access to the extra publishers and certified ad networks in the Ad Exchange, through their AdWords or AdSense
interface. Similarly, advertisers who use other participating ad networks can get the benefits of the Ad Exchange.
What does the Ad Exchange mean for the display advertising ecosystem?
Sellers in the Ad Exchange:
•	 Can make the most money for their ad space, every time a page on their site loads with an ad (called an “impression”). In the
past, too many sellers had inventory unsold or sold for a price below its potential market value.
•	 Get access to many more advertisers, while still being able to control who can advertise on their site.
•	 Benefit from simplified reporting and payments—a single exchange manages it all.
Buyers in the Ad Exchange:
•	 Get access to many more websites and more ad space.
•	 Can use technology that allows them to bid for ad space in real time, depending on how much they value a particular ad impression.