Almost every online marketer uses email marketing. It is a powerful and conversion driven tool for running marketing campaigns, whether through newsletters to retain customers or promotional emails to sell products and services.
As an organisation, you are only allowed to send emails to people if you have a legitimate interest or if they have given explicit consent (opt in), as required under the General Data Protection Regulation (GDPR). In practice, this means that direct email marketing is often used only for existing or past customers. However, by strategically collecting opt ins, you can build a high quality mailing list with future customers, provided that your emails match the preferences they agreed to.