To ensure all bid requests have properly targeted inventory, an assigned ad type, and a proper way to handle backup ads, all accounts have a default ad types/backup ads style in Ad Exchange. The default style is used when styles with other ad types/backup ads setups don’t apply to an impression.
In other words, the default style applies to ad types and backup ads settings for any impressions that aren’t called out in other styles. This default style is initially set to the following:
- (THIS CANNOT BE EDITED) Target all inventory, all geographies, and all sizes.
- (THIS CAN BE EDITED) Ad type defaults to display & text ads.
- (THIS CAN BE EDITED) Backup ads always show a blank space.
A default style that applies to all bid requests is set at the lowest priority level. If no active style higher than the default exists, the default style is applied to bid requests and wins the ad.