Tricky question - emails not tracked

[Anonymous]

We run A/B testing on Marketo and track the downstream impact through a custom Salesforce field. Basically, when a contact becomes an SFDC lead by replying to an email, we have a custom field called "Marketo List" that specifies which email they had received.

The Problem: Unfortunately if a lead uses email forwarding or an email alias, this becomes more difficult. For example, let's say we send Email A to johndoe@gmail.com. When John replies to the email, he uses his corporate address: johndoe@company.com. 

Ideally, John would become a lead in Salesforce with Marketo List = "Email A" so that we can credit Email A for generating the lead. However, since his corporate address is different from the gmail address we originally emailed, the Marketo List is not tracked, and we are unable to credit Email A.

Does anyone have suggestions as to how to fix this?

Thanks!

[Josh_Hill13]

You can attempt to dedupe these records.

If the lead is properly tracked and tagged, the lead can change their email address on the next registration. Have you encountered that situation?

Otherwise, I'm not sure. I bet Eliott or Eric Hollebone knows more.

[Anonymous]

By "reply", do you mean that they click a link in the email?  If so, you should use a different querystring parameter on the link in email A and email B (e.g. www.[your domain]/[your page]?list=A).  Then you would have two smart campaigns whose smart list tab has a Fills Out Form trigger with a constraint of "Querystring contains list=A" or "Querystring contains list=B" and their flow section would set the "Marketo List" field value to either "A" or "B".