Hierarchical organization imposes a useful discipline on your own analytical approach to your content, as hierarchies only work well when you have thoroughly organized your material. I recommend putting a lot of effort into designing a logical system based on the user's view - rather than say, departmental structure, though that might play a role. See the Navigation section for several illustrations of navigational mechanisms. I've laid out some of the principles that went into the structural design of this site. Many of them should be generally applicable to other content-rich information sites.
Many people have difficulty grasping abstract information spaces.
Those who are best at it tend to be programmers who often don't comprehend or sympathise that most of the user population lacks spatial skills and has difficulty understanding the structure. One way to resolve that is to make the structure visual and explicit rather than something that people have to build up as a mental model. An overview map can be very helpful to your users. Corp. All Rights Reserved.