Canonical links are also known as “preferred links”. When search engines have to deal with duplicate content, they have to choose which link should be favored over all others that contain identical page content. Matt Cutts, Google Engineer, defined canonicalization on his blog as: “Canonicalization is the process of picking the best URL when there are several choices“.
Content duplication is one of the most common issues(or challenges) webmasters and site owners must face. There are many different ways to deal with content duplication. The canonical link element is one of the methods used to resolve this issue. The canonical link element was recently endorsed by Google, Yahoo! and Bing.
Another popular search engine like Ask dot com has recently implemented the canonical link element. Most Content Management Software like WordPress, Joomla and Drupal have recently implemented the canonical link element in their code. I will talk more in detail about the “Canonical Link Element” soon.