Agency: A company that provides advertising-related services to their clients.
Under most circumstances the advertising agency will be independent from the company that wishes to sell a product or service. The advantage to hiring an outside contractor lies in being able to obtain a fresh perspective and creativity in developing effective campaign ads. Some companies, however, choose to develop an “in-house” advertising agency, believing this will lower costs and increase message continuity. Any company, with adequate funds, can of course utilize both “in-house” and outside contractors for advertising.