The New Canonical Link Element
As a matter of SEO, avoiding duplicate content is crucial. With our clients, many times what we find is that they have not purposely duplicated their content, but rather overlooked problems with their site that cause their content to be accidentally duplicated. This often occurs when pages or products are accessible via multiple URLs, due to categorization or poor organization. This goes beyond a site that is accessible with and without the “www,” or with example.com AND example.com/index.html, it also affects many online businesses who have affiliates, link partners, and other people linking to their pages with affiliate-appended or mistyped URLs, as well as database-driven sites that have issues with differing versions of the same product or page showing up in multiple categories (each time with a different URL). In these cases, the search engines can view the differing URLs as unique pages but with duplicate content, assigning a penalty or ignoring the pages altogether, but keeping the “juice” from incoming links separated among those pages.
Fortunately, a new link element announced last month and supported by all three major search engines could help to solve many of these issues, and give link builders, SEOs, and web masters a way to tell the search engines exactly what the “real” URL is. This element, link rel=canonical, can be placed in the head section of any page to tell the search engines what the canonical URL for that page’s content is. So if you have an article that appears in two or more places on your site, like example.com/article.html, and example.com/category/article.html, you can specify the former as the canonical URL, and avoid duplicate content and direct any link juice flowing to the latter to the real page for the article.
Originally announced at SMX West in early February and reported on various blogs, a follow-up post regarding the new element appeared on the Google Webmaster Blog on February 12, explaining its use and giving live examples, including Google’s “trusted tester” Wikia.com. ClickZ’s Eric Dafforn also wrote a great article explaining the element and its uses in detail.
For those who want to implement the element themselves, simply place the following in the head section of the page you want to use it for:
<link rel=”canonical” href=”http://www.example.com/correct-url/” />
This will signal to the search engines that the original source of the page’s content on your site is whatever URL you place in the tag. So if you have 3-4 versions of the URL whereby that page can be accessed, all links (both internal and external) that point to any version of the page will be credited to the specified canonical version of the page.
It will be interesting to see some of the changes that occur in the coming months for content management systems that have traditionally had problems with duplicating content, and whether or not they adopt the new element as a fix. As for link builders like us, we will be doing our own tests to see how we can maximize its effect for focusing link juice on the best pages and driving rankings for the most competitive keywords. For more on our link building services, contact us today.
