Add-On Releases - SEOvB - Link Canonicalization for vBulletin Stop Duplicate Content NOW!

Squash vBulletin Duplicate Content Completely with Canonical URL's!
Courtesy of SEO vBulletin Services
tags: seo, vbulletin, vbulletin seo, link canonical, canonical

Google, MSN, and Yahoo have just relased a new tag for stopping duplicate content even further. Combining a good and valid vBulletin Robots.txt file along with the new canonical tag can destroy any duplicate content penalty your vBulletin powered forums may have had going on.

Originally Posted by Search Engines

Carpe diem on any duplicate content worries: we now support a format that allows you to publicly specify your preferred version of a URL. If your site has identical or vastly similar content that's accessible through multiple URLs, this format provides you with more control over the URL returned in search results. It also helps to make sure that properties such as link popularity are consolidated to your preferred version

Canonical Link URL Faq
Is rel="canonical" a hint or a directive?
It's a hint that we honor strongly. We'll take your preference into account, in conjunction with other signals, when calculating the most relevant page to display in search results.

Can I use a relative path to specify the canonical, such as <link rel="canonical" href="product.php?item=swedish-fish" />?
Yes, relative paths are recognized as expected with the <link> tag. Also, if you include a <base> link in your document, relative paths will resolve according to the base URL.

Is it okay if the canonical is not an exact duplicate of the content?
We allow slight differences, e.g., in the sort order of a table of products. We also recognize that we may crawl the canonical and the duplicate pages at different points in time, so we may occasionally see different versions of your content. All of that is okay with us.

What if the rel="canonical" returns a 404?
We'll continue to index your content and use a heuristic to find a canonical, but we recommend that you specify existent URLs as canonicals.

What if the rel="canonical" hasn't yet been indexed?
Like all public content on the web, we strive to discover and crawl a designated canonical URL quickly. As soon as we index it, we'll immediately reconsider the rel="canonical" hint.

Can rel="canonical" be a redirect?
Yes, you can specify a URL that redirects as a canonical URL. Google will then process the redirect as usual and try to index it.

What if I have contradictory rel="canonical" designations?
Our algorithm is lenient: We can follow canonical chains, but we strongly recommend that you update links to point to a single canonical page to ensure optimal canonicalization results.

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 www.example.com vs. example.com vs. help.example.com, but not example.com vs. example-widgets.com.

Sounds great can I see an example in action
Sure, here is a wordpress blog that has implemented canonical URL's already: http://obamanewssource.com Our vBulletin powered site that has made this implementation is only a test site.

How can I check if its working
Go to your showthread page, and hit view source, and search for "canonical" and you should see it automatically added. If its not automatically added for whatever reason, remove the product file thats attached and make this simple template edit to the end of your vBulletin headinclude template (it's a good idea to do this on all headinclude templates)

<if condition="(THIS_SCRIPT == showthread) OR (THIS_SCRIPT == showpost) OR (THIS_SCRIPT == printthread)">
<link rel="canonical" href="$vboptions[bburl]/showthread.php?t=$threadinfo[threadid]<if condition="$pagenumber>1">&page=$pagenumber</if>" />
</if>
<if condition="THIS_SCRIPT == index">
<link rel="canonical" href="$vboptions[bburl]" />
</if>

Tip: If you allow only access from www, or non-www version of your content, make sure your vBulletin path is set correctly!

Install Instructions
Upload attached product.xml file to your vBulletin forums using the built in product manager

Uninstall Instructions
Sorry to hear the modification isn't working, to uninstall it, simply use the uninstall function of the product manager

[davidg]

Adding both lines from BirdOPrey5 and Smitty in one like this :

<if condition="(THIS_SCRIPT == showthread) OR (THIS_SCRIPT == showpost) OR (THIS_SCRIPT == printthread) OR (THIS_SCRIPT == forumdisplay)">
<link rel="canonical" href="$vboptions[bburl]/showthread.php?t=$threadinfo[threadid]<if condition="$pagenumber>1">&page=$pagenumber</if>" />
<link rel="canonical" href="$vboptions[bburl]/forumdisplay.php?f=$foruminfo[forumid]<if condition="$pagenumber>1">&page=$pagenumber</if>" />
</if>
<if condition="THIS_SCRIPT == index">
<link rel="canonical" href="$vboptions[bburl]" />
</if>

Is this correct ?