Can I mix and match placements across different email newsletters or websites?

This is strongly discouraged and could result in lower performance.

For our system to work best, placements that are visible at the same time should all be part of the same container and it is best to avoid unused placements within a container.

To ensure a good diversity of ads, our recommendation system has to consider all the placements within a container at recommendation time, and it relies on the container configuration to know which placements will be present. If some placements that are part of a container are not present in an email or website it could result in our system recommending a high paying ad in a placement that is never seen by a user, resulting in lower performance.