In an effort to eliminate duplicate content or ugly URls, Google, Yahoo and Microsoft announced a joint effort, to tackle this problem. Users are now allowed to point their preferred version of a URL (or Canonical URL). If your site has identical or vastly similar content that’s accessible through multiple URLs, this format provides you with more control over the URL returned in search results. It also helps to make sure that properties such as link popularity are consolidated to your preferred version.
Here is an example: www.iblogzone.com, iblogzone.com, iblogzone.com/, iblogzone.com/index.html, internet.iblogzone.com.. are all different (note the last one which is a sub-domain). Therefore, I can just include the canonical tag and all the previous versions of URLs will suggest to point only at www.iblogzone.com.
You can also find out more about this new element by reading what the search engines have posted about this new open standard. You can read a blog post or help center documentation from Google, Yahoo’s blog post, or Microsoft’s blog post.
If you’re interested, you can see the slides Matt Cutts presented last week to announce this new element:
Or better yet, Matt Cutts did a three-minute video with WebProNews after the announcement to describe the tag, and you can watch the canonical link element video for another way to learn about it. Watching the video is the easiest way to learn about this new element quickly, according to Google’s Chief Engineer.
I now that this subject is more for the tech savvy, nevertheless, if you know some basic HTML, you should have no problem in placing this new tag. What do you think?