What type of value makes the best contact key?

Choosing a unique identifier as the best contact key is sound practice in Salesforce Marketing Cloud because a unique identifier ensures that each contact can be uniquely recognized and tracked within the system. A unique identifier is typically a number or string specifically designated to a single contact, preventing any potential overlaps or confusion that could arise from using other data types.

By using a unique identifier, you reduce the risk of data discrepancies or issues with duplicates. For instance, if a contact changes their email address or phone number, the unique identifier remains unchanged, ensuring consistent reference to that contact across various interactions and campaigns. This is vital for effective customer relationship management, as it provides a stable point of reference for all marketing and communication efforts associated with that contact.

In contrast, other options like email addresses, phone numbers, or names can change over time or may not be unique across a database. For example, multiple individuals might share similar names or even an email domain, leading to potential confusion. Therefore, leveraging a unique identifier allows for a more reliable data structure within your marketing efforts.