Display campaign audience configuration is important because it is the primary means of targeting.
In a display campaign, audience targeting acts as the primary means of targeting. Depending upon the market targeted by the display campaign, it may also be beneficial to _exclude_ certain audiences. These "negative audiences" can be useful in shaping campaign performance.
Type of targeting available including direct website placements using URLs, so-called "in-market" audiences (behaviors indicating shorter-term buying interest), persistent interests known as "affinity" audiences, and demographics audiences which might include age, gender, income level, homeownership, and parental status. There are "customer list matching" audiences similar to what is available on Facebook - the list is used to match to audiences with similar characteristics and behaviors.