In Visual Communication From Theory to Practice, they first cover the Shannon and Weaver communication model. At the time, it was created in relation to telecommunications, but was found to be applicable to all forms of communication.
Their model was extremely simple, with a spot for Source, Transmitter, Noise, Receiver, and Destination. There was no section for feedback, which they continue to describe as a necessity in design and advertising. The presence of a beta testing stage allows for a test run, a period to iron out the wrinkles in the project. It also is a great way to gauge public reactions, and to take estimates on statistics like sales figures and the effectiveness of the message being conveyed. It's much like public speaking. When giving a lecture, it helps to see nods or other bodily gestures as feedback to know that the audience is understanding the message. If there is no feedback, you can't know that your message is getting lost, or going over someone's head.
The noise was also an interesting section. Listening to a professor talk while they make far to many hand gestures is difficult. The extra fluff or stuff that gets lost creates a barrier that the viewer or listener must deal with. They mention the arts and crafts movement and the movement away from redundancy. This moved into modernism and the push for minimalism. Function over aesthetic. However, in transmission, and the sending of information, redundancy helps to cement an idea or get it across faster. This I agree with to an extent. There is certainly an extent to where repetition of an element is too much. Repetition generally causes a design to lose it's initial sparkle.