In That's Not What I Meant by Dave Pollard he discusses how an audience may receive a presenter's message in ways the presenter may not expect. He also touches on the (lack of) usefulness of Powerpoint as a communication tool.
I have read many analyses on the art of communicating and practiced different styles of presenting but I can truthfully say that you get little help from feedback sheets...people either like you and what you are saying or they don't. It comes down to their "world view" and how the issue affects them. It helps to try and cover all views while presenting a specific message.
