We currently have a client with an ecommerce website and they currently list the same items in different categories. The way it works is it is a single record that is referenced in the different categories it is in. So the content on those pages, except for the breadcrumb, is the same. So my thought was using the canonical tag in the head, however the link would also show on the preferred page. so for example [domain.com...] would have <link rel="canonical" href="http://www.domain.com/widgets/widget.html"/>. After my long explaination my question is since I would have to include the link on all of the pages including the preferred page is that going to be an issue?