For once the major search engines have worked together to try and make our job a little easier. This comes with the release of a tag we can use to help us fix duplicate content resulting from a URL being indexed more then once.
Duplicate content is a big problem in SEO. Either someone else may have scraped your website and stolen your content or you may have a canonical URL problem which is resulting in your entire website being indexed more than once as separate pages.
When search engines find duplicate content on one site or between two sites it will choose the most trusted page and use that. But sometimes with dynamic content such as news feeds and dynamic URLs it is hard to tell a search engine it is looking at the same page.
A basic example of a canonical URL would be example.com and www.example.com
These could be read as two separate pages even though they are the same page but with a slightly different address.
The common way to address this is to use a redirect from one page to the other which is called a 301 redirect. But these can be hard and sometimes impossible to implement on a site.
The new way is to add a tag to the <head> section of the page.
<link rel=”canonical” href=”http://www.example.com/ ” />
This new tag is supported by Google, Live and Yahoo and is expected to spread throughout the smaller search engines too.
Adrian Mursec – SEO Programmer
