So let me, once again, knock down this clay pigeon by starting with a quote: "The single biggest problem in communication is the illusion that it has taken place." George Bernard Shaw
My experience in corporations, and my study of corporate culture, indicates strongly that many people don't want their conversations to be public; information, after all, is power. Others never want to say anything in public; meetings show that distinctly. And still others hog the conversation, regardless of medium.
And communication itself can be a form of power, as Dilbert shows, because obstruction is power, whether not responding (http://dilbert.com/strip/2003-03-03) or creating confusion through responding (http://dilbert.com/strip/2007-03-25).
The medium is not the solution to interaction. You can't change people's personalities or corporate politics through a medium.