Date Added: Jan 2010
All of the interfaces between horizontal teams and vertical functions are "Not created equal." You can display the relative importance of interfaces graphically. You can also stimulate important conversations, debates, and decisions using this technique and make it clear where leadership attention is focused. Specifically, the author depict some interfaces as large and hot requiring significant investment of attention and resources; the author depict others as small and cool, meaning that while significant, the interface is not super-critical or urgent.