On the web, there’s raging paranoia and misunderstanding regarding the definition and effects of having duplicate content on a website. Today, Google set out to put the duplicate content issue to rest once and for all (at least for duplicate content issues within a site) with the…
drum roll please…
In brief, a webmaster can place this tag in the head section of an HTML document to specify what the canonical URL of a page should be. You can read more about the mechanics of the new tag on the Official Google Webmaster Blog.
For search engine optimizers, this innovation signals the establishment of a new best practice for page coding: Each webpage should contain a “canonical link tag”. The canonical link tag also eliminates a mess of duplicate content issues caused by database drive websites and may prove to be a far more effective means of preventing identical versions of pages from being indexed than Robots.txt, nofollows, 301 Redirects, and .htaccess workarounds.