There are about 5,000 agencies in the U.S. alone, ranging from tiny operations to large global concerns. There are huge international agencies, with different departments or subsidiaries that focus on specific types of advertising, and independent agencies that specialize in a variety of fields, including consumer, business-to-business, financial, travel, entertainment, and health care advertising. When considering what type of agency you want to work for, there are a few issues to consider. In general, the bigger the agency, the more clients it has. One of the most practical reasons to work at a large agency is job security. If a large agency loses a client, the people staffed on that account are more likely to stay and be absorbed into other teams than they would be in an agency that depended on a few major accounts. As a rule of thumb, watch out for an agency in which one account represents more than half of its billings.

Another significant reason to work for a big agency is variety. In addition to more accounts, large agencies are more likely to win national and international accounts. Most large agencies rotate employees through different accounts during their careers so they have a broad base of experience - they also offer training programs and a clearly defined career track.

Of course there are drawbacks to working at a large agency - there's more competition in larger agencies, it's harder to switch between departments, and it may take longer to move up the ladder. And if you're not sure you know what area of advertising you want to work in (creative, account, or media), a small agency offers exposure to more areas of the business and more of a chance to move between departments. There's also the chance to work directly with higher-ups. However, instead of formal training programs you would find at a large agency, you may find yourself in a sink-or-swim situation at a small agency. Some people love this, but others need more guidance.

Freelancing for agencies

Since the consolidation of the early 1990s, agencies have developed a greater affinity for freelancers. Many claim that the fresh blood adds diversity and helps keep up the quality of their work. But the trend is also the result of bottom-line considerations: freelancers are cheaper to employ. Agencies don't provide them with benefits, and when the work is done, there is no outplacement cost and no unemployment cost. For an employee, the lack of a guaranteed paycheck, no loyalty, and no benefits can pose a problem. But if you do good work and make a name for yourself, there is the potential to make more cash than you could as an agency employee.

The in-house route

Some corporations have in-house advertising departments, though many of them only exist to manage outside agencies. They frequently use freelancers and other outside sources for art, copy, design, and production work.

If you are a recent grad, it will be hard for you to get a job in an in-house advertising department. Most corporations want people with experience and a thorough understanding of all the components that contribute to a campaign: production, media planning, research, and traffic. These hires also need specific technical knowledge - the kind of stuff you only really learn on the job.

If you have no experience but you're determined to get into an in-house advertising position, your best bet is to find a job in a different department in the company of your choice. Learn about the corporation, its products or services, business practices, and its clients. At the same time, get to know people in the advertising department. As an insider you'll find out about openings first, and you may have a leg up on outside applicants.