Ask Enquiro » canonical tag

Long Articles – Another Canonical Tag Use

Chris Davies — Mon, 22 Jun 2009 23:43:48 +0000

The canonical tag has a lot of applications, and one of them is helping to simplify duplicate content issues. One of these situations frequently occurs with long pieces of content which have been broken out over several pages to improve usability. This is common for content publishers such as newpapers, but also happens with other types of sites. It’s common to use pagination links such as these ones (from Lester Chan’s WP-Pagenavi plugin) to help users and engines find the rest of your article.

One great B2B content development strategy can be publishing transcripts of webinars, podcasts or conference calls. These transcripts can easily run into thousands of words, and pagination can be a good choice for readability, however it quickly becomes a duplicate content issue. One client recently had a webinar transcribed which ran into 14 pages. To start with, that potentially creates 14 sets of Meta Data to be written, and 14 different places where people could link. While the content is broken into pages around the themes within the webinar, it’s all around a topic which is quite niche to begin with.

This is a classic case where existing best practices would have tried to focus the authority on the first page, and attempted to reduce the duplicate potential of the other pages by using a combination of links, 301 redirects and the Robots Exclusion Protocol. Now we can use a much more straightforward solution in the canonical link tag.

In the example I mentioned before, you would implement the tag across all 14 pages. The tag has the effect of telling the search engines "this is the preferred version, and the one we like the most". It also transfers signals like PageRank to the canonical (preferred) URL. The tag would look like this:

This will help focus link juice and authority, as well as help deal with possible duplicate content issues.

7 Things to Know About the Canonical Tag

Jody Nimetz — Wed, 13 May 2009 20:08:39 +0000

My previous post on "What is a Canonical URL?", mentioned the use of the recently released (February 2009) canonical tag. The tag itself is pretty easy to use, but we thought that we would share some additional pointers on using the canonical tag.

The canonical tag is applied to the duplicate content URLs. It is to be placed in the tag of the duplicate pages. You are simply adding the preferred version of the URL. You are instructing the engines that these URLs should direct to the preferred URL.
Google (and the other major search engines) will understand that the duplicates (with the canonical tag) all refer to the canonical URL (the URL that you want to be the authority that visitors will see.)
Page Rank will be transferred as well (according to Google)
You can use relative links in the canonical tag. For example, product.php?item=12345 as opposed to http://www.your-site.com/product.php?item=12345
You can specify a URL that redirects as a canonical URL
You cannot use the canonical tag to suggest a canonical tag on a completey different domain.
Google does take canonical suggestions into account across sub-domains.

Remembering these seven items can help ensure that you are leverging the canonical tag properly and that you are letting the engines know what URL it is that you want to be communicated.

What is a Canonical URL?

Jody Nimetz — Fri, 08 May 2009 23:14:59 +0000

Lots of discussion about canonicalization and canonical URLs lately. I’ve discussed URLs and URL structure a few times in the past. We thought that we would help illustrate the idea of canonical URLs. From an SEO point of view here is the definition of a canonical URL:

Canonical URL: the search engine friendly URL that you want the search engines to treat as authoritative. In other words, a canonical URL is the URL that you want visitors to see.

Quite often canonical URLs were used to describe the homepage. The typical example used is that most people treat the following URLs as the same:

www.example.com
example.com
www.example.com/index.html
example.com/home.asp

The fact is that these are all different URLs. From a search engine perspective, this can cause a bit of an issue. Hence the idea of canonicalization. Canonicalization is the process of picking the best URL (to present to the search engines) when there are multiple choices available. Typically a search engine, such as Google will attempt to pick the best URL that they feel is the authority for that page. However, sometimes they may in fact select the wrong one. Now let’s suggest that you have product pages that depending on how the user navigated to the pager returns a different URL… same page but different URL, now we have a duplicate content issue. Not to mention the nightmare for interlinking and external link inventories.

The easiest way to avoid this is to let the Search engines and the users know which is your “preferred URL” a.k.a canonical URL. One suggestion is to redirect all of the variations to your canonical URL (the URL that you want to be the authority). In February, the major search engines announced another solution with the canonical tag. This tag gives you control of the content that you want the engines (and users) to see.

Matt Cutts of Google fame has discussed duplicate content and canonical tags a number of times. One of the questions that he was asked included:

Q: So when you say www vs. non-www, you’re talking about a type of canonicalization. Are there other ways that urls get canonicalized?
A: Yes, there can be a lot, but most people never notice (or need to notice) them. Search engines can do things like keeping or removing trailing slashes, trying to convert urls with upper case to lower case, or removing session IDs from bulletin board or other software (many bulletin board software packages will work fine if you omit the session ID).

We have seen sites that have upwards of 15 versions of the same page but with different URLs. The simplest solution is to have one final destination URL. An easy way to do this is through the canonical tag or by redirecting all of these pages to one authoritative page. The canonical tag is simple to use, all you need to do is add this tag to specify your preferred version of a URL inside the (head) section of the duplicate content URLs.

Canonical simply means relating to or belonging. It also means reduced to the simplest and most significant form. Just remember that a canonical URL is the simplest and most significant (authoritative) version of the URL that you want to be seen.