What is the canonical tag?
This is an html attribute that has been created by Google so that webmasters can get help to manage duplicate content when it’s a duplicate. This tag is more of a reference and a citation. This tag informs the search engines and pass all the ranking to the original page. This can be understood in simple language as giving the credit of the content to a main page from where it has been duplicated.
Why you should use the canonical tag?
This is a very important tag in a webmasters toolkit. There is no other way to manage duplicate content, and duplicacy lead to a penalty. An example of its usage is when a commercial site is built for its range of products and may have multiple URLs. The content might be duplicated among these URLs since a product offered may not just fit in just a single category but in more. In these cases a canonical tag can be used for which will avert the risk of getting penalized for content duplication.
How it is used?
The Canonical tag is very easy to use. It is a one line code.
<link rel="canonical" href="http://domain.com/url" />
This one line of code needs to be used very carefully and if not used appropriately may end up being disastrous.
This canonical tag needs to be included and placed as a part of the HTML header in a webpage between the opening sections and closing sections of the source code. Every tag in the ‘href’ section must refer to the replicating page.
It is a good thing for the marketing experts to keep in mind that if all interior tags refer back to the same homepage, then the interior pages might not show up in the search result.
Sometimes while doing a search engine optimization job on a site, the biggest issue that is faced is content duplicacy. The content management systems have a tendency to create different versions of a page which have similar content as these pages are required for many instances. This causes a confusion during a search as the search engine become unsure of which version needs to be indexed.
301 redirect and the ‘Canonical Tag’
Looking at it from the angle of digital marketing, many similarities can be found between 301 redirect and the ‘canonical URL tag’ feature.
301 redirects and Canonical tag communicate with the search engine that several pages should be considered as the same. The only difference though is that the 301 redirects all traffic whether it is the users or the crawlers whereas the canonical tag works only for search engines. 301 redirects has a cross functionality across domains. This helps, because it can redirect a page from one domain to another, while the canonical tag solely works from a single domain.