You sell great jeans. You have perfect style and wash. The problem is you also have duplicate content. The same pair of jeans is listed on your site alphabetically, by high price first, by low price first, by price, by color, and by size. That same description appears again and again, and technically, this is duplicate content. And duplicate content is very bad if you’re trying to play in Google’s sandbox. So, what is the jeans’ retailer to do? Implement a rel=canonical tag.
What is Rel=Canonical?
This tag indicates to Google that you have duplicate content; the page with the tag is the one you’d prefer that Google index. Google doesn’t have to listen, but as Matt Cutts says, the canonical tag is a “strong hint” and, usually, the search engine abides by webmasters’ wishes in this regard.
How Do You Do It?
Regardless of whether you sell jeans or not, adding a rel=canonical link is fairly easy.
Here is our sample website: http://www.superawesomejeans.com/product.php?item=darkwash
And here is what we do to specify the canonical link:
Copy this link into the <head> of each of the non-canonical versions of the page.
Now, if you want Google to recognize the canonical version of a URL, enter in the HTTP header:
And there you have it. Now, the question becomes when should you use rel=canonical as opposed to a 301 redirect? That’s what we’ll look at next time.