[wp-hackers] Canonical integration into core

Wed Feb 18 09:10:16 GMT 2009

On Feb 18, 2009, at 8:37 AM, Matt wrote:

> With the exception of paged comments, when does WordPress ever present
> two pages with the same content on them where this tag could actually
> be used? Yes, a theme may show duplicate content on category, archive,
> etc pages, but this tag cannot be used there. Feel free to prove me
> wrong on this by providing some example URLs of where there's
> duplicate pages (that this tag can be used on), besides
> /comment-page-x.
>
> -1 on this by default. But +1 for adding it when paged comments are
> enabled (otherwise it would be useless, because there wouldn't be any
> duplicate pages).

It's not just about what WordPress does. For example:

http://example.com/about/

and

http://example.com/about/?from=email

will serve up the same pages in most WordPress installs. If you add  
the rel="canonical" link to the <head>, the latter will have all links  
pointing to it counted toward the first one. That's, for me, one of  
the main uses of the tag.

Best,
Joost