The Chartered Institute of Marketing defines Marketing as: “the management process responsible for identifying, anticipating and satisfying customer requirements profitably." and also states that "Marketing is crucial for business success. Without paying attention to what it sells, what price it charges, how it promotes its products, and where it sells them, no company can survive."

An Advertising Agency is defined by them as "..... a service business dedicated to creating, planning and handling advertising (and sometimes other forms of promotion) for its clients - an organisation which specialises in providing services such as media selection, creative work, production and campaign planning to clients"

So an Advertising Agency needs to be able to understand and carry out some Marketing in order to correctly identify your target market in the media and therefore create a media plan. A Marketing Specialist needs to be able to define your market in more ways than an agency but they do need an Ad Agency who can implement a media plan that reaches your target market. Marketing Specialists are usually PR Specialists too, and this is a full time job with a whole different set of skills and contacts than that of an Advertising Agency.