I am the maintainer of a breadcrumbs module, "Crumbs", https://drupal.org/project/crumbs
The module has been added into commerce_kickstart, and since then has (as to be expected) plenty of users.
There are some issues, but overall it seems the feedback is positive.
However, if you search "drupal breadcrumbs" on Google, you don't find it anywhere.
I think the problem is that the path alias does not contain "breadcrumb" or "breadcrumbs". So, it shares the same fate as "Hansel breadcrumbs", which also has a poor ranking for "drupal breadcrumbs". Which is sad.
I wonder if anything can be done about this.
One idea I had was to create a placeholder project at drupal.org/project/crumbs_breadcrumbs. But, I don't know whether this would actually help, and I'm afraid it could be considered as spamming. So, I want to check with the project review team before doing anything like this.