We'd be happy to answer these questions about your contacts! A contact can be placed in more than one list because Constant Contact is designed to recognize contacts by their email addresses and remove duplicates. So if you schedule a campaign to all your lists at once, contacts will only receive it once. You can always see these contacts are on multiple email lists by exporting your contacts and including Lists in the fields you want to include in your export. Once you download this file you can see all the lists a contact is on.
On the other hand, segments relate to lists because you can then take these segments and add them into a list. Our segment tool allows you to customized groups of your contacts based on specific criteria. This criteria can be email activity, list membership, or even custom contact details you may have created. I hope this helps!
Frankie P. Community & Social Media Support
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