In small agencies, employees may do both creative and account service work. Larger agencies attract people who specialize in one or the other, and indeed include a number of people in specialized positions: production work, Internet advertising, planning, or research, for example.
An often forgotten, but integral, department within an advertising agency is traffic. The traffic department regulates the flow of work in the agency. It is typically headed by a traffic manager (or system administrator). Traffic increases an agency's efficiency and profitability through the reduction of false job starts, inappropriate job initiation, incomplete information sharing, over- and under-cost estimation and the need for media extensions. For example, In small agencies without a dedicated traffic manager, one employee may be responsible for managing workflow, gathering cost estimates and answering the phone. Large agencies may have a traffic department of five or more employees.