by arnold » Fri Jan 18, 2013 8:33 am
A canonical link element helps to prevent the duplicate content issues by specifying the "canonical", or "preferred", version of a web page. It is a important part of search engine optimization, when the duplicate content issue arise due to same content is accessible from multiple URLs. For example xyz.com/page.html is accessible by xyz.com. To avoid this a canonical element is inserted in the header section of the webpage code.