Hi Matt,
This really depends on the contract you have with them.
Most of the time, this needs to be a reversible import. This means that you need to be able at the end of the rental contract, to be able to delete all leads from this source that have not reacted to your campaigns at least once during the contract duration. The term "reacted" may mean different things, depending on the contract. Most of the time, it means that the leads should have at least filled out one form.
You should comply with this contract rule when time comes, as vendors usually have trap addresses in their lists that would detect if you send them an email after contract has ended. This means you need to prepare in advance, otherwise, it will be very difficult to know what lead you should delete at the end of the contract.
My advice in this case is that you take a few precautions:
- Import the leads in a dedicated static list (one separate list for each import date and source) that no one will temper with.
- Create for each of the imports a smart list with the following criteria: lead was created - source is : the static list. This will give you the actual list of leads you created during import (as it may happen that you already had some of them in the DB)
- Create another smart list that select all members of the previous ones, combined with the filter "not filled out form" to have the list of leads to be deleted when time comes.
Another point you also need to weight in: the quality of these DB... If the quality is is not good, you will end up increasing your hard bounce rates and unsubscribe levels and impair the deliverability of your whole Marketo instance. If you are not sure, use another simple and cheap emailing tool, upload the list there, create a few emails with CTA's to Marketo Landing Pages and forms. Only the interested people will enter Marketo.
-Greg
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