A mailing is a marketing tool of online advertising
. A mailing is an advertising mail that is used as part of e-mail marketing. Based on a defined customer target group and the available mailing lists, advertisers send mailings with, for example, product information or special discount promotions. It should be noted that the e-mail recipients have agreed to the sending of mailings and other promotional e-mails with their opt-in. Otherwise, these are unsolicited spam mails.