I came across an interesting tidbit on Creating Passionate Users by Kathy Sierra (via Scoble) about using mind maps to outline ideas — in her case, to outline a book, each chapter, and each topic within a chapter before committing pen to paper. While Kathy’s underlying message was to praise the tablet PC, its never about the tool — its about what the tools enable us to accomplish.
Her reasoning for mind mapping versus traditional outlines makes sense: " when you use a linear format rather than pieces radiating out from the center, the brain imposes a hierarchical structure on the content, regardless of whether one was intended. And this matters. It changes, even if subtly, the way you process and understand the material. "
Of course, I’m a big believer in use case analysis, which accomplishes much of the same. Its a non-linear way to define business processes and system architecture while keeping you from getting bogged down in implementation issues, such as what the UI looks like, what platform it needs to be on, etc.