That was a very good question and we haven’t really done a ton blog post about how we compute breadcrumbs. So, I send an email to the people who had done the blog post and sort of asked them about that. And, the rough answer that I got back is that you should have a set of delimited links on your site that accurately reflect your site’s hierarchy. So, the thing that I would add as color to that is still early days for breadcrumbs.
Think about the situation with site links. Whenever we started out with site links, it took a while before, for example, we added the ability in Google Webmaster Tools where you could remove a site link that you didn’t like or that you thought was bad. So we started out and we did a lot of experiments and we’ve changed the way the site links looks several times and we have different types of site links. You know, within a page and you know, the standard ones that you’re familiar with.
For example, I had seen some prototypes where it was in the red snippets sort of gray line above the regular snippet. And I think having it in the URL was kind of nice but it could still change over time. So it still a little bit early to say exactly here’s where you might go in the Webmaster console and suggest hierarchies and stuff like that.
The best advice I can give is, is try to make sure that it is a setup of delimited links and it does accurately reflect your site’s hierarchy, and if you do that, you’ll be maximizing your chances and in the meantime, we’ll keep working on ways to improve breadcrumbs because users do seem to like it. And, if there’s any changes, just keep an eye on the Google Webmaster blog and I’m sure, if there’s any new announcements, they’ll announce it there.
by Matt Cutts - Google's Head of Search Quality Team