SharePoint Areas and Topics - How to simplify?

I was meeting with a customer talking about SharePoint. One of the things that came up was how we can organize the site and taxonomy. Of course, as I expected, finding a simple way to explain SharePoint Areas and Topics is a bit difficult. I find that its one of those things that once you understand it you get it, but trying to explain it in a simple “30,000” foot way to people who don’t really want to understand the details is difficult.

So, does anyone have simple anologies that really conveys the thoughts quickly and easily?