The term “Postmaster” is used by online email service providers, ISPs, and other email platforms to refer to the person responsible for the technical management of email sending on behalf of an advertiser or a provider specializing in email campaign delivery. Major online email services and ISPs offer dedicated resources for postmasters, providing them with essential information on the technical management and filtering of email campaigns. These specific pages are designed to help postmasters optimize email deliverability and ensure their messages effectively reach their intended recipients.