Google has launched a new Webmaster Help video, where Matt Cutts (Head Of Search Spam) tells about the multiple breadcrumb trials on the pages. A breadcrumb trail is a set of link that can assist you to understand and navigate your site’s hierarchy.
When you markup the breadcrumb data in the body of a web page, Google can recognize it and use it to understand and present the information on your pages in its search results page. Matt suggests you to arrange all the breadcrumb pages in the right hierarchy.
On the other hand, Matt said that you should not worry if you don’t use multiple breadcrumbs because majority of the people don’t use it.
Therefore you can have only one set of breadcrumbs. In case your page hierarchy is already set up to have pages pointing to multiple categories, Matt said that it doesn’t affects your other sets of breadcrumbs on the page. Google will pick the first one and use others as a way to get a better understanding about the overall structure of your site.
You can watch the below video of Matt Cutts about multiple categories on e-commerce page.
Can i markup the breadcrumb data in Blogger? If yes, How to do that?