Did you confirm that there are actually duplicates in the database and that Marketo did not just add the duplicates to your list?
If Marketo recognizes the leads based on the email address, it will indeed be de-duplicate them, meaning it will update the lead records with any additional/changed information contained in the list you are importing.
The terminology in the message is probably a bit inexact in this case, but that is what Marketo is doing.
Another thing to keep in mind -- if you are importing into a specific static list, Marketo will still be adding your existing leads to the list you have created. They were already part of your database but will now have been added to the static list as well.
I think that what happened might be that the four existing leads might have been updated, and not duplicated. Perhaps the message "Existing people imported" is inaccurate. If you can confirm that any of the four existing contacts did get duplicated, I would suggest you open a support ticket with Marketo.
Thank you, Jeffrey, Justin and Rafael!
I got it - Marketo updates the leads and adds existing leads to the static list :)
I have a question with regards to importing new leads to an existing static list. So, I have a static list which is synching with a SFDC campaign, but will need to add more leads to that static list as I go. I need these new leads to sync with the same SFDC campaign making sure only the new ones are added, with no duplicates... I hope this is clear.
Does anyone know if Marketo will add the previous leads to the SFDC campaign all over again along with the new leads added?
Thanks in advance for your help.