SFMC Subscribers

Every successful marketing campaign starts with a subscriber—an entity who has given explicit consent to receive communication from your company. Whether you collect this information via online channels (like web sign-up forms capturing first name, last name, email, and age) or compliant offline channels (such as registration forms at restaurants or real estate agencies), you must follow proper anti-spam laws like CAN-SPAM before registering their data.

Once registered, Salesforce Marketing Cloud (SFMC) provides multiple ways to house this data. However, everything ultimately ties back to a single master database in Email Studio: The AllSubscribers list. Understanding how data flows into this central hub is crucial for any marketer.

        Subscriber Lists

SFMC allows you to group subscribers into standard lists, with a single list typically accommodating around 500,000 subscribers. The data flow here is direct and automatic:

• Any Personally Identifiable Information (PII) or profile data you add to a standard Subscriber List is instantlyand automaticallyadded to the master All Subscribers list.

        Data Extensions (DEs)

For more complex, contact-based data models, SFMC utilizes Data Extensions. Unlike standard lists, Data Extensions categorize information into two distinct functional buckets based on subscriber behavior and profiles:

• Sendable Data Extensions: These store a subscriber's PII/profile data (such as Subscriber Key, email address, and gender) used to route marketing communications. When creating a Sendable DE, you must define a Send Relationship, linking your custom fields to the master Subscriber Key in the All Subscribers list.


• Non-Sendable Data Extensions: These store behavioral or transactional details. For example, an e-commerce company needs to store invoice numbers, purchase history, bill amounts, or product specifications (color, size) post-purchase. By default, data extensions that are not explicitly marked as sendable become non-sendable, and their contents are never added to the master list.

Data Storage Comparison

Data Models

When you capture subscriber data from an online webinar or an offline event, you need a secure, structured place to store it. In Salesforce Marketing Cloud (SFMC), this is where your data model comes into play.

SFMC offers two primary data models to organize your information. Choosing the right one depends entirely on your campaign goals and data complexity.

1. The List-Based Data Model

If your marketing strategy relies on straightforward communication, the list-based model is a perfect starting point. It uses standard SubscriberLists to store basic Personally Identifiable Information (PII) such as names, emails, age, and location.

• CapacityLimits: A single subscriber list can hold up to 500,000subscribers. To store more, you have to spin up a new list.
• FixedStructure: It is a non-relational model. Every list you create automatically adopts the same rigid profile template.
• Best Use Case: Simple marketing practices where you only need basic personalization, like dropping a customer's first name into an email greeting.

2. The Contact-Based Data Model

When you are ready to scale into advanced, data-driven marketing, you need the contact-based model. This model utilizes DataExtensions(DEs), which function like relational database tables.

• RelationalFlexibility: You can link multiple distinct tables together. By utilizing SQL joins or AMPScript, you can pull data from different sources seamlessly.
• UnlimitedScaling: Unlike lists, Data Extensions have no subscriber storage caps.
• DataSeparation: You can segment your data into two types of extensions:
• SendableDEs: Stored PII data (emails, subscriber keys) used to target communications.
• Non-SendableDEs: Stored behavioral data (purchase history, product types, bill amounts).

For example, an e-commerce brand can link a Sendable DE (customer email) to a Non-Sendable DE (recent purchases) to dynamically showcase the exact items a customer bought right inside their email.