One of every search engine’s major goals is to remove duplicate pages from its results listings, showing only the most relevant of the duplicate pages, to help users get quickly to the page they’re looking for. This can result in pages from the “wrong” domain showing, for example http://example.com/page.html rather than http://www.example.com/page.html, if the website is visible on both http://example.com and http://www.example.com .
To help make webmasters more aware of when this happens, Google has started issuing notifications when it has selected content from an alternative domain rather than from their own domain within its Webmaster Tools website.
While it is useful to be notified of this, there are a few things webmasters can do to make sure that Google selects the right URL for their content in the first place:
A common cause of duplicates is a website that is visible on both http://example.com and http://www.example.com, or visible on both http://example.co.uk and http://www.example.com . It is usually best only to show the content on one domain and redirect vistors from any secondary domains to the primary one
If you are unable to prevent the content showing on secondary domains, add a rel=”canonical” link element [http://www.google.com/support/webmasters/bin/answer.py?answer=139394] into the HTML <head> or HTTP header. This tells Google that it should consider the linked URL to be the primary one for the content.
This is just one of many Site Optimisation techniques that can be deployed to help your site’s search engine rankings. Contact Us to find out more.