Human communication, verbal or other, differs from the conventional or "medium" model most basically in that it is interactive. It involves anticipated feedback in order to take place at all. In the medium model, the message is moved from the sender-position to receiver-position. In real human communication, however the sender has to be not only in the sender position but also in the receiver position before he or she can send anything. (Ong, page 176)

   To speak, one has to address another or others. People in their right minds do not stray through the wood just talking at random at nobody. Even to talk to yourself you have to pretend that you are two people. The reason is that what I say depends on what reality or fancy I feel I am talking into, that is, on what possible responses I might anticipate. To speak, I have to be somehow already in communication with the mind I am to address before I start speaking.  I might arrive at this through past relationships, by an exchange of glances, by an understanding with a third person, or in countless other ways. I have to sense something in the other's mind to which my own utterance can relate. (Ong, page 176)

   Human commmunication is never one-way. It not only calls for a response, but is shaped in its very form and content by the anticipated response. This is not to say that I know how the other will respond to what I say. But I have to be able to conjecture a possible range of responses at least in some vague way. I have to be somehow inside the mind of the other in advance in order to enter with my message, and he or she must be inside my mind. To formulate anything, I must have another person already "in mind". (Ong, page 176-7) 

   This is the paradox of human communication. Communication is inter-subjective. The media model of communication is not. There is no adequate model in the physical universe for this operation of consciousness, which is distinctively human and which signals the capacity of human beings to form true communities wherein a person shares with another person inter-subjectively. (Ong, page 177)

   The practical implications for effective communications are significant. When speakers forget or ignore the interactive nature of communication, as frequently occurs in organizations where speakers mistake their hiearchical power over their employees for an actual capacity to force listeners to listen, the outcome is predictably diastrous.

The implications for leadership

In effect, leaders need to stop "telling" people what to do, and instead, engage in conversation. Here's an excerpt from chapter 11 of The Secret Language of Leadership:

   "We all know what a good conversation is, even if we enjoy it all too rarely. Think of an interesting dinner party where participants have fresh points of view but don’t try to thrust their opinions upon others; where the discussion is inclusive and participants create openings for each other, drawing everyone into the discussion and drawing each other out; where the talk is lively but participants speak respectfully even when they disagree; where they share relevant stories rather than make abstract pronouncements; where participants are willing to speak on a variety of subjects but are not afraid to admit ignorance or mistakes; where the language is intelligible and free from jargon; where the flow of serious thought is lightened by periodic laughter; where people feel it is easy to make their contribution; where they listen to each other with genuine curiosity and learn.

"Such interchanges are atypical in the communications of managers with their staff, of teachers with pupils, of parents with teenagers, or of politicians with their electors. The communications of authority figures traditionally follow a different path, starting from what the authority figure “knows,” what the system or program “requires,” what the institution “wants.” It’s talking at people rather than with people. All too often, it involves lecturing and preaching rather than participating in a conversation that makes everyone want to continue the dialogue."

For more on the role of conversation in leadership, see chapter 11-12 of The Secret Language of Leadership.

References
    Stephen Denning, The Secret Language of Leadership: How Leaders Inspire Action Through Narrative, (Jossey-Bass: October 2007): chapter 11-12.

    Stephen Denning, The Springboard: How Storytelling Ignites Action in Knowledge-Era Organizations. Boston, London, Butterworth Heinemann, October 2000, chapter 5.

   Walter J. Ong, Orality & Literacy: The Technologogizing of the Word,  Routledge: London and New York, 1982.