DM is the abbreviation of English direct mail advertising, which literally translates as "direct mail advertising", that is, sending promotional materials to consumers, families or companies by mail or gift. It is also manifested in direct magazine advertisements. There is no essential difference between the two, and both emphasize direct delivery (mailing). Therefore, DM is a new advertising carrier different from traditional advertising media such as newspapers, television, radio and internet. Traditional advertising media sell content, and then sell the circulation to advertisers twice, while DM is an advertising channel that sells directly to target consumers. DM can be divided into broad sense and narrow sense, including advertising leaflets in broad sense, such as leaflets distributed in streets, shopping malls and supermarkets, discount coupons of KFC and McDonald's, etc. In a narrow sense, it only refers to a set of advertising brochures!