Direct advertising includes all forms of sales appeals, mailed, delivered, or exhibited directly to the prospective buyer of an advertised product or service, without use of any indirect medium, such as newspapers or television. Direct advertising logically may be divided into three broad classifications, namely, direct-mail advertising, mail order advertising, and unmailed direct advertising. All forms of sales appeals that are sent through the mails are considered direct-mall advertising. The chief functions of direct-mail advertising are to familiarize prospective buyers with a product, its name, its maker, and its merits and with the products local distributors. The direct-mall appeal is designed also to support the sales activities of retailers by encouraging the continued patronage of both old and new customers. When no personal selling is involved, other methods are needed to persuade people to send in orders by mail. In addition to newspapers, magazines, radio, and television, other special devices, order promotions are designed to accomplish a complete selling job without salespeople. Used for the same broad purposes as direct-mail advertising, unrolled direct-mail advertising, includes all forms of indoor advertising displays and all printed sales appeals distributed from door to door, handed to customers in retail stores or conveyed in some other manner directly to the recipient. With each medium competing keenly for its share of the business, advertising agencies continue to develop new techniques for displaying and selling wares and services. Among these techniques have been vastly improved printing and reproduction methods in the graphic field, adapted to magazine advertisements and to direct-mail enclosures the use of color in newspaper advertisements and in television and outdoor signboards more attractively designed and efficiently lighted. Many subtly effective improvements are suggested by advertising research. Direct advertising ______.