From Information Architecture for the World Wide Web by Louis Rosenfeld & Peter Morville
"As information architects, we can also use invisibility to our advantage. There is no question that our discipline suffers from the iceberg problem, as illustrated below. Most of our clients and colleagues focus on the interface, without appreciating the underlying structure and semantics."
"Savvy designers know to look beneath the water line, understanding the importance of blueprints and wireframes to site development. But few people, even within the Web design community, realize the critical role the lower layers play in building a successful user experience. This ignorance of deep information architecture results in short, superficial, and often doomed projects.
Those who recognize the need to build structures from the bottom up have an immediate advantage over those who skim along the surface. And because this structural design is hidden from the outside world, these early adopters get a big head start. Once competitors see what the Episcopalians call "the outward and visible signs of inward and spiritual grace," it's often too late. By the time Borders Books & Music realized the power of Amazon's user experience, they were already years behind. Page 358, Chapter 18: Business Strategy"
Note: The graph at left was revised from the original only in line weight and color. This drawing main emphasis ought to be the black text and not the pyramid (triangle) shape - as you can see in this example the pyramid shape is receded in tone and color to push the text forward. This revised graph's blue wave shape emphasize the division between the definition of the interface and the underlying structure and semantics. On page 358, The original drawing outline is too heavy, text weight is weak without the contrast to differentiate the shape and text, plus the wave line is too light to show the division between the top (Interface) and the bottom (Information Architecture, etc).
The use of the pyramid does works for the book's iceberg analogy but to a point (no pun intended), a better approach to this graphs is to use a ice cube - a cube has a flat surface, like our monitor screen has a flat surface and so forth. See results here.