It has probably been mentioned before and is worth mentioning again, money is really in the list. Why? Because with opt-in lists, you get to keep your readers on the hook by providing them with information, promotion, and other campaigns in order to entice them to buy again from you.
Basically, opt-in lists are lists of email addresses of customers with their consent. This means that after the customer had closed the transaction in a particular web site, there is an option on whether or not they wish to subscribe to the mailing list of the online business for any future promotions, newsletters, or campaigns that they would like to be informed of.
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