You may have heard the term "Ad Agency" often getting thrown around, but what IS an ad agency? An advertising agency can be defined as "an agency that designs advertisements to call public attention to its clients." An agency is a company that is hired by a brand or company to create and manage advertisement campaigns. Campaign goals often center around awareness, lead generation and sales. Within an ad agency there can be several disciplines, including media planning, consumer analytics, social media, planning, and strategy. Most mid-sized to large, successful agencies today are owned by one of the "Big Four", WPP, Interpublic, Omnico, and Publicis - large advertising and public relations holding companies. Many agencies offer a full service (traditional and digital services), while others focus on direct marketing, events, or interactive marketing, etc. Agencies are often regarded as fun and interactive places to work as they often feature open, creative-thinking spaces where advertisers can ideate together, and a good work-life balance. Agencies with the largest revenues include BBDO, McCann Erickson, Young & Rubicam, and JWT.