This document discusses different types of communication. It defines communication and identifies its key elements: source, message, channel, and receiver. It then categorizes communication based on identity, medium, and number of participants. Intrapersonal communication occurs within oneself, interpersonal is between two people, group involves 3-12 people, and mass communication transmits messages through media to a large audience without direct feedback. Mass communication aims to inform, persuade, entertain and influence the public.