Which data model is preferred when the number of subscribers exceeds one million records?

When working with a large number of subscribers, specifically exceeding one million records, the preferred data model is data extensions. Data extensions are designed to handle complex data structures and large datasets more efficiently than lists.

Data extensions provide greater flexibility in organizing and managing subscriber information. They allow for the incorporation of multiple custom fields and can accommodate various data types, making them ideal for segmentation and targeting in email campaigns. Additionally, data extensions can be linked to other tables, supporting relational data, which is essential when managing extensive data collections.

Lists, while useful for smaller groups of subscribers, do not scale as effectively in situations involving large amounts of data. They have certain limitations compared to data extensions, such as fixed data structures and limited functionality in terms of segmentation. Groups and data filters serve specific purposes for organizing and categorizing data but do not themselves store data in the manner required for large-scale subscriber management. Thus, data extensions emerge as the optimal choice for handling more than one million subscriber records.