Can Marketo handle duplicate email addresses for different people?

Hi Guys,

New to Marketo and apologies bringing this old thread back up.

Trying to follow @Sanford Whiteman‌ approach to send multiple emails to the same email address.

But for some reason in my Request Campaign step, no campaigns are appearing for me to assign against Request Campaign:

Am I missing a step before hand?

Hi Sarah - Marketo has another workaround for both these scenarios.

a) If you want to import lists with duplicate email addresses you can ask Support to change your dedupe criteria for list import. Email address MUST be one of the criteria, but you can add one or more other criteria to it to refine the dedupe. To dedupe it must be an exact match for ALL criteria (there's not if this plus this type logic, it's not that smart)

Down side is ALL list imports from that point will use this extended criteria, so you have to be certain all your list imports follow the same scenario you've set up or you'll accidentally create a bunch of duplicate new leads. Talk to Marketo Support for more info on that since they have to set it up for you.

b) Sanford is 100% correct that the Send Email will only send to one email address. I've hit the exact same scenario as you with needing to send the unique promo codes, and instead of using the Request Campaign (which I always avoid if possible as it puts tremendous pressure on your Marketo system, plus I'm lazy and don't want to build too many campaigns!) many of us out here use this process within a single Smart Campaign flow:

Send Email

Wait Step (length depends on size of list)

Send Email (add Choice - If Not Sent Email is this email)

Wait Step

Send Email (add Choice - If Not Sent Email is this email)

Repeat as often as you need to cover all potential dupes.

However I will second Sanford's suggestion to read the post by John Mattos he linked to on the unexpected behaviour of deliberate duplicates in the system.

Marketo, as a database, ​fully supports multiple records with the same Email Address. Email Address is not a unique identifier.

However, that is not the whole story because Email Address is still the only ​lookup key ​for most UI-based (as opposed to API-based) operations. Standard list imports, for example, will locate the target lead by its email address. (In contrast, API-based imports can be set to lookup on another key, like the built-in Lead ID or even a custom string field.) And a list import with 3 rows referring to a single email address will ​only ​ever update a single lead, continually updating its values. This post will shed more light on the logic.

Your example of sending separate emails is actually slightly different from the unique key vs. lookup key decision. It's principally to stop you from looking like a spammer. Marketo will only send to one email address per Send Email step. If you want to send to multiple qualified leads with the same address, then instead of calling Send Email directly, you can trigger a Request Campaign ​on another campaign that in turn uses ​Send Email. Such individual ​Request Campaigns ​can send to multiple leads that happen to have the same email address, since there is no batching-and-deduping.