Canonicalization Element
I have been noticing that a lot of websites are now including the Canonicalization Element (CE).
This is a good thing for the robots to identify the ‘core’ or the ‘authority’ page of multiple duplicate content.
“A canonical page is the preferred version of a set of pages with highly similar content.” is Google’s definition of CE.
Now this definition is general, and the exampled they used was for a website that contain domain.com or putting the www’s infront of the domain name. Most websites with Windows Server have this problem, and it’s basically the same page but a different address/link.
The point of using the CE is to ‘hint’ to the robots which page is the ‘authority’ out of a set of pages on your website that have HIGHLY similar content. If that doesn’t ring a bell in your head or have a lightbulb turn on, then you need to stop reading this post. 
Blogs are NOTORIOUS for having d u p l i c a t e content. Let me explain…..
I write this post, and I include it in 1-2 blog categories, AND added a few tags. I also added the nice permalinks.
The issue is that this post will appear in my categories (2pages), tags (I have 4 tags=4pages), and of course the post link.
2 cats + 4 tags + 1 post link = 7 pages on your website with the SAME CONTENT. This is why it’s important to put a No Follow Attribute on category pages, tag pages, and the archives.
The Canonicalization Element is supposed to help avoid having this problem of duplicate content.
So on what page should you put this CE? I think it would make sense to ONLY put it on the actual post page.
If you put it all on the 7 pages, then the effect of the CE will be wasted. Now you’re back to square 1 in having the robots pick which page is the authority or core page out of the set of pages.
Here’s the definition again “A canonical page is the preferred version of a set of pages with highly similar content.”
The canonical page = Post page. Set of pages = categories, tags, and archives.
New definition = “The post page is the preferred version of the category, tag, and archive pages which display highly similar content”
Make sure to use this SEO factor the correct way!
You seem to have misunderstood what you should put in the rel=canonical tag.
>> If you put it all on the 7 pages, then the effect of the CE will be wasted. Now you’re back to square 1 in having the robots pick which page is the authority or core page out of the set of pages. <<
No, because the rel=canonical tag will be identical on all 7 pages, and will therefore specify which page out of the 7 you would like to be the canonical.
The canonical plugin doesnt do what you wrote about.
If the canonical element was placed on each page with just 1 page link, then it would be fine.
The canonical plugin doesn’t do that. It puts different links on every different page that has the same content.