I like very much organising information in hierarchical outlines through PIM software (also names tree outliners/ treepads/ etc). I wouldn't feel comfortable if I do not have information organised this way. I have always wondered how come MS Word does not have this functionality or at least a third-party add-on. Yet, my personal observation is that the majority of people feel completely ok without any such tool.
It seems to me that people would rather use tags or they'd just pile up information without any special description and prefer a search function instead of browsing throughout their own structures. Whenever I have showed someone the glorious capabilities and beauty of a hierarchical PIM, I have never met an expected "WOW effect" but sheer disinterest. :)
Is there any research on specific inclinations people have towards organising information?