The act of maintaining a list so that hard bounces and unsubscribed names are removed from mailings. Some list owners also use an email change-of-address service to update old or abandoned email addresses (hopefully with a permission step baked in) as part of this process.
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Building Your Business with an Opt-in List
Before revealing the secrets of the trades, here are myths and fallacies that need to be cleared before one indulges into building an opt-in list.