I spent those last few days with three separate groups of designers. I insisted with all three on the importance of setting-up a proper blueprint as a priority.
I have a academic background in retrieving and manipulating data. It was a given that I would have an inclination for the information architecture aspect of user experience. The issue comes with the appetite of clients for screens. They want things asap and we want to please them. There is a focus on the page, the interactions, the pop. Sometimes, when the project doesn't seem complex, it even seems like it's okay to skip IA.
It can be okay sometimes. Your experience will help to draw that line. One sure thing, if a project that needs IA doesn't plan it, the people involved are going to get frustrated.
Unuseful screens are going to get created. Wrong design patterns for things as important as menus or tables are going to be chosen. And coming back from that is difficult. Time will be lost, work will be trashed.
I see the Information Architecture documentation as a comfy pillar, always available. Reading your flowchart should give anybody a crystal clear idea of what your application does. A proper IA makes you confident of the goals you are pursuing with your screens.
Yes, I really like IA.
Illustration by abd-alrahman, used under Creative Commons Attribution-Noncommercial 3.0 License.