For years now, Pardot has changed the configuration of this tool for unique prospect identification. This is logical, SalesForce bought Pardot as the typical Inbound or Automation B2B tool and at that time they had the email data as the only field. However, the logical next step was its increasingly integration with SalesForce CRM and that is when the well-known CRM ID appeared as unique data.
Topic: SF Account Engagement Pardot