Just came across a post on the Google Webmaster Central blog about their support of the new canonical link tag.
The canonical link tag tells the search engine what the preferred URL for a page should be. It goes in the and looks like this:
<link rel="canonical" href="http://mysite.com/page.html" />
This is extremely useful for sites that can have multiple versions of a page thanks to variables such as tracking parameters or session IDs. Another benefit is that PageRank is passed to the canonical URL.
To understand more about the implications of this new tag it’s worth reading through the comments to the post and in particular Google’s response to them.
This definitely sounds like something I should add to my 12 essential web site building blocks.
[via Website Magazine]