I am currently migrating to ExactTarget and wondering how to best use Lists and Data extensions.

I have a large volume of Subscribers and according to the docs: http://help.exacttarget.com/en/documentation/exacttarget/solution_guides/using_a_list_versus_a_data_extension/ it seems I should be using Data Extensions to store them. This is fine, as DE's Import job runs relatively fast.

However, from what I've experimented with, it seems like I can only create an Email Send job if I link this data extension to the Subscriber list or create a Publication list to work off of and run and Import job on the List. This is extremely slow, as I end up having to import millions of rows into the list. This especially becomes a problem if I'm trying to update data on an hourly cadence.

Is there a way to directly send off of a Data Extension? If not, what is the best way to deal with Email Sends on a large volume of Subscribers? Please let me know if I'm going about this completely off the mark.

Thanks in advance!

3 Answers 3


Yes, you can send directly to the DE. Upon creation, you need to make the DE a SENDABLE DE. Otherwise, you cannot. For a more thorough explanation of everything ET Data Extension, have a look here

  • When I try to make a DE sendable, it asks for a relationship to Subscribers. Doesn't this mean I have to have an entry in the Subscribers list for every entry in the DE?
    Jul 23, 2014 at 20:26
  • Yes, BUT... it will add the relationship at send time if it does not exist currently.
    – Timothy
    Jul 23, 2014 at 20:29

Yes, you may send directly off a Data Extension. In the DE setup screen, checkmark the Sendable box, and map the email address in your DE to the EmailAddress column in Subscribers.

If you don't checkmark Sendable, the DE won't be offered in the list of available DEs when you initiate a send.


For large data sets of subscribers you use data extensions that you connect to the central marketing cloud subscriber entity via a send relationship as mentioned before.

Most systems that handle the volumes you reference use some sort of id field for identification. This should be used as field for your subscriber relationship.

If you import data from another email tool but also have a master record system like an ERP or CRM you should probably consider using the id provided by those systems as they will have more meaning for the architecture you are likely going to setup.

An example: in commerce systems orders (a likely starting point for email communication) are tied to the purchasing person via a customer Id field. This customer Id is the one you would want to use in the marketing cloud as well as it will allow you to associate not only the customers themselves but also their order history for emails based on new orders or status changes. With the send relationship established through the customer Id the Marketing Cloud will always know who to send to even if the email address changes over the lifetime of the customer.

For this reason only use the email address if you have absolutely no other choice to identify individuals. Email addresses can change for a person and that will give you a major headache if you use them as unique key.

In general: defining the contact-subscriber relationship is part of your future data strategy and something you should invest some thought in as it will have major implications. Rewriting SubscriberKeys in the Marketing Cloud is always a painful thing and requires paid Salesforce professional services.

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