Today at the SMX West conference, Google, Yahoo and Microsoft just announced a new tag that will have a major impact on reducing the amount of duplicate content issues found online and it will help website owners reclaim valuable link popularity.
In this article Canonical URL Links by WordPress specialist Joost de Valk he explains the tag and reasoning behind it. I will give a quick synopsis myself below but his article has some more detail if you need it.
These two URLs lead to the exact same page but the search engines interpret them as different URLs:
You see the information from the question mark onwards in URL #2 is actually just tracking information that was added to show that a person who visited the site arrived after clicking on an advertisement from “campaign1”. Unfortunately, since search engines see these as different URLs the link popularity coming from a specific advertisement is placed on the campaign URL instead of the actual URL (#1); this is not a good situation because the more link popularity a link has the better chance it has of ranking in searches.
Today, the big three search engines announced they still see the URLs separately unless you place a new tag called the Canonical Tag (say that 10 times fast!) in the heading of the affected page. In the case of the example I used above the canonical tag would look like this:
< rel="canonical" href="http://www.xyzname.com/company/">
What that tag says is the search engines should consider http://www.xyzname.com/company/ as the main address of this page. As a result, the link popularity for all variations of this URL will be consolidated to the canonical URL specified in the heading of the page.
Who is Affected by This News?
This is amazing news for anyone using Pay Per Click marketing will be all over this as well as anyone with an advertisement such as a banner or text link where tracking intelligence has been appended to the URLs.
From a slightly different standpoint this has a great affect on anyone with a content management system (CMS) where two URL versions of a single page may have been indexed; the rewritten search engine friendly URL and the exposed database-driven URL. With this new tag it is entirely possible to retrieve some significant link popularity and substantially increase your rankings.