The expression breadcrumbs is used sometimes in web design. The origin is the Hansel and Gretel story by the Brothers Grimm, where Hansel drops bread crumbs as they go into the forest which they later use to find their way back home again.
In web pages, "bread crumbs" are meant to show you how you got to a page, what section of the web site that the page belongs to, and how to get back again. Sort of like the browser's back button, except not necessarily. If you follow the "most logical" path, it'll match. But if you got there via a cross link...well, that depends on the website.
On WoWWiki, bread crumbs are displayed in the top left hand corner of the page, and look something like this:
- Glossary » Breadcrumb
WoWWiki makes no attempt to emulate a browser back button with the breadcrumbs. Here, the breadcrumbs are meant to be informative as to what section of the wiki the page belongs to, and where to go to find more pages like it.
Additionally, in World of Warcraft, this term is used to describe a quest whose sole purpose is to lead you to a new zone or area to explore.