For example, at the pre-introductory and introductory stages, it is important to create awareness. During the introductory stage, it is also important to create trial.
Mass communication can deliver same message to large audiences, at low cost per person.
Mass communication is one-way, and feed back can be slow and inaccurate. Targeting messages to specific target audiences can be difficult. Interpersonal communication is fast, and allows two-way feedback. Can tailor message depending on needs of the audience. Can be very expensive when the process has to be repeated for many audiences, and when the various audiences are spread over a large geographical area.