Confirming our previous reports, Google has announced and explained why and when it’s showing breadcrumb navigation in its search results.
Google says it may show these site heirarchies “for a small percentage of search results” when it improves the search snippet with more context about the link being pointed to. What’s pretty cool is that each link in the green breadcrumb is clickable, giving searches immediate access to different pages on the listed web site.
Related Topics: Google: Web Search
Is there are specific structure you need for your breadcrumbs for Google to pick them up?
it looks similar to RDFa tagging, but looking at the code it doesn’t seem like there is anything to indicate that. how is Google determining it’s a breadcrumb vs. a normal link?