Final answer:
A full-service agency offers an extensive array of marketing and promotion services. These agencies can implement a cross-platform strategy to provide unified branding messages across various mediums, such as those described in Naomi Klein's analysis of advertising trends.
Step-by-step explanation:
An ad agency that provides its clients with a comprehensive suite of marketing, communication, and promotion services is known as a full-service agency. Such agencies handle a wide array of services including but not limited to creative development, media planning and buying, digital marketing, branding, and public relations. In comparison, a creative boutique focuses mainly on creative design; a media buying service specializes in purchasing media space and time; an account service agency manages the relationship between the client and the agency; and a buzz marketing agency focuses on generating word-of-mouth for the brand.
Understanding the role of a full-service agency is pivotal in the context of the shift in advertising tactics as identified by Naomi Klein, highlighting the importance of unified messaging across different platforms and how an ad agency can implement a cross-platform strategy similar to the example of Miller beer's advertising campaign.