When Hansel and Gretel laid down a bread crumb trail, the birds ate it and they got lost. The pebble trail is what got them home.
Well, it's a catchy term. Some UXer started using it and it stuck. The problem I have with it is that rarely are breadcrumbs using the metaphor of 'path you took'.
That said, they do tend to be 'the path home' so I guess the analogy works.
That's a great question - I have a post I've been working on for a while where the intro is:
I tend to over-analyze so I have sources and other info I'm still coalescing. Most of it is still in note form. I hope to publish it within a month of relaunching my site.
Here are some of the sources I have put together.
I try to look at items like breadcrumbs from 3 aspects: UX, IA, & SEO. The article is more heavily biased in terms of SEO vs UX. Meaning - you can provide breadcrumbs and should, but beyond the basic text breadcrumb and location. Architecting your breadcrumb should be about IA and SEO.
Having said that - I have no clue when I will relaunch my site, but the most important information can be found in those links.