New Canonical Link Tag Will Help with Duplicate Content

Just like the lamb lying down with lion, but the big three search engines came together for a rare joint effort to announce the launch of a new feature that will help ease the world’s duplicate content problems. The new feature, called the <link> tag tells the search engines what version of the URL is the correct one to want index.

The link tag goes in the <head> section of the page of  looks like this:

<link rel=”canonical” href=”” />

The search engines have been doing a pretty good job figuring out the right URL when people use redirects properly, but it’s not always easy to get it right–especially when we build these nutty sites with 50 different URLs pulling up the same content. This change should help a lot of webmasters sleep easier knowing that their proper, canonical URL will be indexed and given all the link juice it deserves. I look at it like a page by page sitemap to tell the search engines what URL to index.

Official blog posts about the new link / canonical tag:




Coverage on other blogs:

Search Engine Land

Joost already created a WordPress plugin for this feature

3 Reasons to Use rel=canonical, 4 Reasons not to use it

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  1. Kyle says

    Is this Canonical Link Tag relating to just on site tagging or across the web? For example if I wrote an article and posted on my site first and then submitted to several article directories, search engines will know that I am the original source? Help me out please.

  2. says

    We’re all still trying to understand this new feature, too, but as far as I understand, it is for domains that you own/control, and only for identical content, not scraped or syndicated content pages.

  3. Dan Schulz says

    You’re right, Dave. It’s only for domains you control. In other words, it’s meant to be used only within a site, not across multiple sites (unless those sites are hosted on multiple subdomains associated with the same domain).

    From the Google blog:

    (Not sure if you folks accept HTML or not, so I’m going to copy/paste it as unformatted text.)

    Can this link tag be used to suggest a canonical URL on a completely different domain?

    No. To migrate to a completely different domain, permanent (301) redirects are more appropriate. Google currently will take canonicalization suggestions into account across subdomains (or within a domain), but not across domains. So site owners can suggest vs. vs., but not vs.

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