Hello There,
Please find inline inputs below:
1. Data share between AAM and Google/FB involves a unique identifier at both ends which in general scenario is the deviceID. for AAM, it is AAM ID and similarly for Google/Facebook it is this Id which gets identified. As customerIds are linked with AAMUUID only, using this information a unique customer can be identified.
2. For ITP2, currently, Audience Manager team is evaluating workarounds for current and anticipated tracking prevention announcements. In the immediate term, we’re working on a scalable solution to capture full referer URL data for all customers. Further out, we’re exploring ways to leverage first-party cookies to track Safari users.
For more information about user identification in two systems, please follow this document.