The document discusses advertising agencies and their role. It defines an advertising agency as an organization of professionals that provides creative and business services to clients related to planning, preparing, and placing advertisements. Advertising agencies employ various professionals like account executives, media buyers, creative directors, and copywriters who help advertisers with activities such as planning, preparation, placement of ads, public relations, sales promotion, and more. Agencies house specialized talent and expertise across these areas that most advertisers cannot match with in-house teams alone.