Canonical link elements have been introduced to assist search engines (namely Google, Yahoo, and MSN) to find the difference between relevant and non-relevant content within the same content. Our website can be accessed by typing any of the following into an internet browser: bugon.com, www.bugon.com, http://www.bugon.com, and www.bugon.com/index.htm. To begin, when other websites are linking to your website, the goal is to have the majority of sites linking to the same version of your website. Since accessing our website through http://www.bugon.com and http://www.bugon.com/index.htm will bring you to the same website, we would like search engines to recognize http://www.bugon.com as the main page so in order to avoid confusion we added the canonical link element to our index.htm page under the head portion of the html.
<link rel=”canonical” href=”http://www.bugon.com”/>
Google, Yahoo, and Microsoft have all addressed the new canonical link element and their browsers will all be fully supporting them:
Of additional value, you can watch Matt Cutts from Google who clearly explains the new canonical link elements and how it differentiates from the 301 redirect.