What does the term "subscriber key" refer to in SFMC?

The term "subscriber key" in Salesforce Marketing Cloud (SFMC) refers to a unique identifier that is used to distinguish individual subscribers and is critical for effective data management. This unique identifier can default to the email address of the subscriber, but it is important to note that it does not have to be the email address. The key allows marketers to maintain a reliable and consistent way to identify users across different marketing activities and databases, ensuring that campaign data remains accurate and up to date.

Using a unique identifier like the subscriber key is essential for tracking subscriber behavior, preferences, and interactions within SFMC, which can help in delivering personalized content and improving customer engagement. By employing a subscriber key, organizations can also handle cases where individuals may have multiple email addresses or choose to update their information over time without losing track of their historical interaction data. This flexibility is vital for maintaining a comprehensive view of subscriber relationships over time.