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Marketing Cloud: Unique IDs 101

For those who are considering implementing Salesforce Marketing Cloud, identifying the unique ID to manage contacts can be a tough decision. But, it's an extremely important one. 
Unique ID’s are a part of the beginning of almost every implementation or migration in Salesforce Marketing Cloud. Below are some things to think about when identifying the unique ID in your instance. 

What is a unique ID?

A unique identifier (ID) is a numeric or alphanumeric string that is associated with a single entity within a given system. Unique IDs make it possible to address that entity, so it can be accessed and interacted with.

One of the first things every customer of Marketing Cloud has to do, regardless of what channels you’re using, is create a unique user ID for their contacts. This is to build out the relational data model in Marketing Cloud.  So as additional data is added in the future  everything correlates back to what the unique identifier is.

Creating a unique ID

One thing to keep in mind when creating your unique ID, is that all facets of the platform require this unique identifier. This is especially important to consider if you think about contact builder and omni-channel messaging. 

Typically, you don't want to use a changeable data point as a unique ID. For example, when a contact's email address changes, you've got two data points on that contact record in Marketing Cloud, the unique ID or subscriber key, along with their email address. When their email address changes, their unique ID is still going to be their old email address. So, it makes it really hard to keep track of that record. 

Another reason why it’s not a good idea to use email addresses' for a unique ID is household messaging. If the email address is the unique ID, you've got essentially one email address for many contacts, which really limits your ability to communicate with people within that household on a personalized basis. 


Unique ID alternatives 

Though not recommended, if your organization doesn’t have any other unique ID, using email is typically the easiest and quickest path. This can happen if your organization is small and Marketing Cloud is the true system of record. 

If you have different unique identifiers across three or four different data sources, an email address might be the best case scenario to try to bring most of that data together within the platform. Lastly, if there are a lot of duplicate records and that unique ID hasn't really served its intended purpose, that might be a good use case for email address to be used as the unique identifier. 

It's also common to see Account ID or a Client ID used, especially if you're a power Salesforce user. If you have Sales and Service cloud, it's generally the best practice to have the Salesforce ID establish and house those contacts, and then pass that into Marketing Cloud, that way they speak the same language. 

Identifying the unique ID is an integral part of your data management strategy in Marketing Cloud. To learn more check out the episode of In the Clouds: Unique ID 101