The demand-side platforms (DSPs)
Demand-side platforms have risen to help advertisers manage all of their exchange campaigns through a single interface. These DSPs utilize the ad exchange's data connection via application program interfaces (APIs), which provide the same functionality as working on the exchanges' own systems. Some agencies and holding companies have built their own DSPs, and many third-party DSP providers have popped up, such as Turn, Invite Media (Google), [x+1], MediaMath, DataXu, and Triggit.
DSPs provide more features than just letting advertisers manage all of their buys in one spot. By aggregating the entire exchange buying process into one system, advertisers can utilize the high-powered algorithms of their DSPs to optimize their bids. These algorithms can be tuned to target a specific cost-per-click, cost-per-sale, return on investment (ROI), or other business goals. They can also provide integration with various third-party data providers to allow for simple access to purchasing inventory. Another recognized benefit to running everything through a DSP is that advertisers can enable universal frequency capping across all of the exchanges they work with.
Because an ad needs to load quickly, DSPs have service level agreements (SLAs) that set how long they have to return a bid for the impression. The standard time frame for a DSP to return a bid request to an exchange is around 50 milliseconds, or one-twentieth of a second!
Bids are generally handled at the cost-per-thousand (CPM) level, and advertisers can choose to vary these bids based on the value of the users each placement is targeting. A common targeting choice is contextual, as exchanges classify their inventory by categories (i.e., sports, entertainment, news, finance, etc.) and sub-categories (entertainment - movie; entertainment - music; etc.). It's probably safe to say that an advertiser involved in promoting a new film would be willing to pay more for to users on movies sites than on financial ones.
Another common targeting option is geography -- by country, region, state, DMA, etc. And because you can mix targeting directives in a placement, you could, for example choose to create a campaign that just targets users on automotive-related sites in California and bid accordingly for that traffic.
It's important to note that advertisers are not manually bidding on every impression in real-time -- not even Superman could keep up with 150,000 ads per second. Rather, advertisers choose targeting settings and a maximum bid for what they would pay for an impression that meets those parameters. As with paid search, analysts can continuously optimize their choices by changing bids and targeting settings to ensure the best possible ROI.
The data layer
The piece of the puzzle that seems to most accentuate the value of exchange buying is the various data that can be leveraged in order to target users. By tagging user browsers via anonymous cookies, advertisers can retarget to their website's visitors on publisher sites by bidding more for those users than their competitors; reaching shopping cart abandoners with multiple ad impressions in the first few days after leaving the site has become a smart way to utilize this feature, for example.
Third-party data providers tag users and then sell advertisers access to identify those users later on an exchange. These companies (such as BlueKai, eXelate, and Experian) can provide user segments such as male or female, age bracket, income bracket, etc. How do they do this? There are various ways. There are data providers that tag users online who are registering product warrantees; they can provide exchange visibility to audiences based on the types of products they own. Other data providers make deals with travel aggregators so that advertisers can (anonymously) target users who have searched for Caribbean vacation deals or European hotels. Some data providers work with social networks that have registration data on millions of users and can help find audiences with specific niche interests.
The most valuable data seems to be that which can help identify in-market users. For example, a data provider signs a deal with a top-tier automotive review site to allow it to tag its users on key portions of the site. Days later, a major car manufacturer is able to buy impressions on other sites to target those same users who were looking for specific car-related information.
Ultimately, advertisers are going to pay more to reach the most desirable audiences to their business. Data empowers the advertiser to be able to better judge the value of each impression as it is passed to them.