List Settings & Customisation
Lists help to organise your Users into groups, making it easier to identify who you want to send to when creating Email Campaigns.
Create an unlimited number of Lists and add Users to as many that are relevant to them e.g. I want to know about Football and Cricket but not about Golf.
List-level opt-outs are stored permanently so you don't need to worry about re-importing Users that have previously unsubscribed.