Thinking about thinking. That's the difference between outliner users and everyone else. They think about thinking. They're aware of their own process. Only people who think about thinking get to a place where they can invest in being more efficient in their thinking. Maybe "only" is too strong a word. Some people say they don't think in outlines. Yeah yeah. But hanging information on a hierarchy makes it easy to forget it and focus on new ideas and relationships. It's a good way to relax intellectually. ";->" [from Scripting News; emphasis in italics mine.]

I live for hierarchical outlines--this is why I'm one of the "folder list" folks rather than the "outlook bar" folks.  Things need to be categorized and subcategorized and grouped and related and such.