Publishers and printing companies are both involved with books, magazines, and newspapers. One type of company is considered part of the manufacturing section, because it produces the physical product: books, magazines, newspapers, and so on. What sector does publishing belong to, since it does not produce a tangible product (until printing transforms it into one)?
secondary, because it transforms ideas into physical objects
primary, because it makes original content
quaternary, because it involves research
tertiary, because it provides a service