Levels of Communication
In reference to Nell's comment about the levels of communication: I think most people organize the levels of communication around the number of people participating: intrapersonal (1 person), interpersonal (2 or 3 people), small group (5-10 people), and public speaking (1 speaker with audiences ranging from very small to very large). And then there's mass communication which involves even more people. And then there's interviewing which is often grouped with interpersonal (because it usually involves 2 people but not necessarily people who are close to each other and is increasingly conducted in groups). And then there's computer mediated communication which is really on a different level because it can be interpersonal (as in e-mail), small group (as in chat rooms), or public (as in blogs or newsgroups). If this doesn't answer your question, let me know and I'll try again.