Hi @Michael_Soprano - Interesting discussion - Adding points from my understanding
In an AEP + Adobe Target integration, identity resolution and profile stitching primarily happen within AEP Identity Service. Multiple identities such as CRM ID, Loyalty ID, Account ID, Email, and ECID can coexist in the identityMap and be stitched together into a unified profile through the identity graph.
More Reference -
When Target is integrated through Web SDK and Edge Network, Target can leverage profile and audience information that has already been resolved by AEP. The Edge Network acts as the bridge between AEP and Target, allowing audiences and profile context to be available for personalization.
While Adobe Target supports only a single namespace as the Target Third Party ID (mbox3rdPartyId), that limitation applies to Target's native profile identifier. It does not prevent AEP from maintaining and stitching multiple identities behind the scenes through the identity graph.
Therefore, in a Web SDK + Edge implementation, audience qualification is driven by AEP's identity resolution capabilities, whereas the Target Third Party ID remains a Target-specific profile identifier used for Target profile recognition. This is one of the key advantages of the Edge-based architecture, where identity stitching and audience evaluation are handled by AEP, and Target consumes that resolved context for personalization.