The advertising industry consists of four principal entities: Advertisers, Agencies, Media and Suppliers. Advertising can be produced directly by the advertisers, or it can be produced with the assistance of an agency, in either case, suppliers often work alongside to help create the finished product. Commercial production house for example, puts ads onto film. Research suppliers that conduct measurement on consumer behavior or audience response also play an important role in campaign development. Many individuals and businesses are involved in bringing an ad campaign to life. Suffice to say, the advertising industry is extremely diverse in its functions and roles. The advertising industry relies on two sources of income to function successfully. The first, which directly supports advertisers, is income from consumers, who buy advertisers' products and services. Advertisers to hire agencies then use that income. The second major source is from the media.