"In a page description diagram, the content areas of the page are described in prose, as in a functional specification. The content area descriptions are arranged on the page in priority order. Typically, I will define the horizontal axis of the diagram as the page priority. Thus, content areas described on the left side of the page are higher priority than those on the right side of the page. […] Ultimately, designers are paid because they are good at thinking about visual relationships. Presumably, an information architect focuses on relationships among information, categories, and content, not among shapes, color, and contrast. The page description diagram is a tool to allow designers and information architects to stay comfortably within their own realms without compromising communication."
It’s true that no matter how hard you explain to clients (and even some slow-to-learn team members), that wireframes do not pretend to represent actual page design, most of them will have a hard time not bickering about layout. Dan Brown’s "page description diagram" seems an elegant solution to practice information architecture without stepping on the designers’ toes and blurring the discussion with clients. I’ll have to try that sometime and see how people react.