Microsoft Monetize - Third-party tracking pixels for creatives
Third-party tracking pixels are used for a variety of purposes such as performing ad verification and collecting data about the creative.
Third-party tracking pixels can be created at either the advertiser or Network level and associated with the appropriate creatives. You can also associate custom third-party tracking pixels with your creatives if you want to use another system to track impressions.
There are many advantages to creating and associating third-party tracking pixels at the advertiser or Network level. For example, creating and applying third-party tracking pixels at the advertiser or Network level saves time by eliminating manual steps. In some situations, instead of creating these tracking pixels for each advertiser, it might be more efficient to create and add tracking pixels at the Network level. These Network-level pixels can then be applied to creatives under any advertiser for the Network.
Also, since creatives are frequently added and removed, tracking pixels can be attached at the advertiser or Network level to avoid having to re-attach the same pixels to numerous creatives, which only simplifies workflows and reduces setup errors.