Look at the top of the forums Brian,

See the huge title of this thread? Right underneath that you see this:

Home » Forums » CoffeeCup Shopping Cart Creator » SCC PRO : Shopping » Verify Cart » Payment » Download ???

That is breadcrumbs. That basically is what they mean by the nested categories, it shows you exactly where you are on the site as if it's showing you each menu choice you made to get where you are. Hope that helps

Grrrreat !!!

Breadcrumbs or breadcrumb trail is a navigation aid used in user interfaces.

Home > Vehicles > Cars > Ford > Crown Victoria

http://en.wikipedia.org/wiki/Breadcrumb_(navigation)