You can use lists to determine the type of content contact should receive. For example, you can create lists like Monthly Newsletters, Promotions, Product Announcements, and send relevant emails to list subscribers.
By default, OnVoard will automatically create contact list Newsletter for new accounts. This is the main list for your account. To keep things simple, you can use 1 main list as the main audience when broadcasting emails.
Difference between Lists and Tags
Lists provide better tooling to manage the type of content a contact can receive.
Contact can opt-in to specific lists when they modify communication preferences. Communication preferences link can be shown along with an unsubscribe link under email footer.
Bulk Add/Remove Contacts from List
How to export contacts from list
List in Workflows
Lists can be used triggers to start a workflow whenever a contact is added. There's also workflow action that allows you to add/remove contacts from lists.