What are "unclassified campaigns"?

In Piano Analytics, we favor a tag-first approach, and marketing campaigns require a minimum of two properties to be correctly processed: src_medium and src_campaign.

If we collect src_campaign with an empty or missing src_medium property associated with it, the source will still be considered a marketing traffic source but classified as “Unclassified Campaign“. Indeed, the source type is only defined by the property src_medium.