I was sure that I’d previously set out my thoughts on this matter but I can’t seem to find them anywhere. Therefore be advised that there follows something of a rant.
I despise the term “breadcrumb” when used in the realm of web design. As far as I can fathom, it was coined by Jakob Neilsen — he of the usable but terribly designed website — to describe the hierarchical indication of your location within a site structure. The term refers to the Grimm fairy tale Hansel and Gretel where the siblings left a trail of crumbs that they could follow in order to find their way back out of the forrest where their evil stepmother planned to abandon them.
All well and good. Apart from one thing: when Hansel and Gretel used breadcrumbs as a navigational aid, they got lost. It was only when they were using pebbles that they successfully escaped the maze of trees.
Metaphors aside, a trail of where you’ve been is not the purpose of the “breadcrumb” device. Returning to where you’ve been is the job of your browsers back button. The “breadcrumb” is supposed to indicate the ancestry of the current page — the category or section to which the page belongs.