Google, Yahoo & Microsoft Unite On “Canonical Tag” To Reduct Duplicate Content Clutter, Vanessa Fox, searchengineland.
The web is full of duplicate content. Search engines try to index and display the original or “canonical” version. Searchers only want to see one version in results. And site owners worry that if search engines find multiple versions of a page, their link credit will be diluted and they’ll lose ranking.
Today, Google, Yahoo and Microsoft (links are to their separate announcements) have united to offer a way to reduce duplicate content clutter and make things easier for everyone.
Specify the canonical version using a tag in the head section of the page as follows:
<link rel="canonical" href="http://www.example.c...swedish-fish"/>
* You can only use the tag on pages within a single site (subdomains and subfolders are fine).
* You can use relative or absolute links, but the search engines recommend absolute links.
This tag will operate in a similar way to a 301 redirect for all URLs that display the page with this tag.
* Links to all URLs will be consolidated to the one specified as canonical.
* Search engines will consider this URL a “strong hint” as to the one to crawl and index.
Canonical URL links, Joost de Valk, yoast.
Joost includes links to Canonical plug-ins for WordPress, Magento, and Drupal.
Live Coverage of Ask The Search Engines at SMX West, Barry Schwartz/Keri Morgret, seroundtable