Canonical Link Tag Information: With so many duplicate web-content links it was only a matter of time before some enterprising individual found a way to truly separate and specify the primary and original content links. This way search engines can focus on the original location as opposed to the myriad of other variations in existence. The answer to the question of reused and copied web page links is what is known as the canonical link tag, also known as the canonical URL tag.
What exactly is a canonical link tag you might ask? Well a canonical link tag is a code segment placed in the header of a website that has closely related web pages with similar content. This canonical link tag allows for the segregation of the similar pages so that search engines, especially Google at present since they came up with the concept, can know exactly what page the website owner wants them to consider for inclusion in their search engine searches instead of the haphazard manner it is done now.
To further specify what this means take the following examples into consideration:
Each of these pages would lead to very similar if not exactly duplicated content or they might be pages that have more accidental clicks and therefore show up higher in search engines as opposed to the page the webmaster actually wants to be the most visible.
The canonical link tag was designed as a way around this common occurrence. The webmaster can choose one of the above links and make it canonical by using a tag in conjunction with the web address in the header. The tag would look something similar to this:
If the webmaster creates a page with urls in the design then the canonical link tag can be used to resolve into these types as well.
As stated the purpose of this canonical link tag addition is to specify the exact page of duplicate or similar content for google and other search engines to crawl and add to their listing. Google does not mind duplicate content if this tag is in evidence because now it isn’t of as much concern.
The canonical link is the one they will strive to add to their listings.
The three main search engines, Google, Yahoo, and Bing, all had similar things to state about the canonical link tag as a new method of focusing search attention on specific web pages. Google stated the most because they originated the idea.
Questions were asked to Google in relation to many aspects of the Canonical link tag. The most prevalent revolved around content issues and linkages. When asked about what can and cannot be linked using these tags Google specified that the tags were meant for duplicate or incredibly similar content.
One example given was that it was ok for a dance shoe selling site to have two or more pages with exactly the same content except for the color of the shoe. The use of the canonical link tag was meant for this.
However, using the tag to try and make a gel insert or other additional shoe parts rate higher than the shoe was not considered appropriate.
One can surmise that if there were many types of gel inserts being listed by the same site that insert could have its own canonical relations. You simply cannot use it across different types of pages on the same domain. A set of shoe pages would have its own canonical link in the header as well as a gel insert page set will have their own canonical tag.
Yahoo made special mention of the absolute and relative nature of link tags and pointed out that both were admissible for use with this type of tag but the absolute linkages were far more desired for simplicity of design and ease of crawling. There were less chances of causing an error in this fashion. The canonical link acts in a manner similar to a 301 redirect and as such acts in that manner to transfer links to the canonical page.
Bing made it a point to remind the web traveling populace that just like the other two major search engines they will consider the canonical URL tag as a suggestion that they take seriously but will not be the final word on what page is included in their search engine site indexing.
They will evaluate content based on what is on the pages and their linkages. All tags must point to pages on the same domain. If there are an canonical link tags on a page that redirects to a separate domain, even if they are labeled similarly, the tag will be ignored. This is considered a type of abuse as attempts to cross-link more than one domain with this will lead to a great deal of work for their poor crawling scripts and improper indexing might occur.
The canonical link tag is an aid to those who wish to specify particular pages for entrance into the search engine index but it is only a suggestion. In a very literal sense these canonical pages are no different than asking a search engine to “Please pay attention to this page more than any other.”