Northern Trail Outfitters uses a number to uniquely identify contacts across different marketing channels.

To ensure that contacts relate across different channels in Marketing Cloud, you need to link the unique identifier used across channels to the Contact ID in Contact Builder. This involves creating Attribute Groups and establishing the relationships between the unique identifier and the Contact ID.

Link the Numeric Field Value: By linking the numeric unique identifier to the Contact ID in Attribute Groups, you ensure that each contact is uniquely identified across channels.

Create Attribute Groups: Attribute Groups in Contact Builder allow you to map the relationships between different data sources and the Contact object, ensuring that the unique identifier is connected correctly for each channel.