An Open Question for Information Architects

I want to ask the Information Architects out there a question:

When designing, do you create hierarchical information architectures? (with the home page at the top of the hierarchy)

• If so, could you explain why you make it hierarchical?
• If not, is there a structure to what you are making, what is it, and why did you do it that way?

A little context: I’ve been thinking about IAs a lot lately (as you can see from my posts). One of my earliest observations is that many of the IAs out there are hierarchical, and I’m wondering how that came to be.

Please, share what your experiences are. I’ll write up a post that summarizes the responses.