On the IA Institute members's list, Christina Wodtke asked about the difference between information architecture and information retrieval. Margie Coles had the answer: wayfaring.
You can see similar suggestion in the shift from task-centered design to goal-directed design, and from goal-directed design to message-driven design. The ACM Ubiquity article, "Why features don't matter anymore: the new laws of digital technology", approaches the same topic. (Message is how I define the the other, oft-missing, part of the mental model.)