In digital advertising, what does 'defaulting' mean?

In the context of digital advertising, 'defaulting' refers to the action of passing an ad opportunity to the next partner. This occurs when a particular demand source or ad partner is unable to fulfill an ad request, whether due to unavailability of suitable ads, restrictions, or other limitations. As a result, the opportunity is then passed along the chain, allowing another partner to potentially fill that slot with an appropriate ad.

This process is essential in programmatic advertising, where numerous parties are vying for placement, and seamless transitions between partners help maximize ad fill rates and revenue. By defaulting, advertisers ensure that the ad inventory is still utilized effectively, rather than leaving it ad-less, which could lead to lost opportunities for engagement and conversion.