Google, Yahoo and MSN Live have introduced a new tag that all three search engines will recognise. The tag which can appear in the head of document will instruct the search engines back to the canonical URL a page.
This mean there is now a new option available to SEO’s and webmasters when fixing duplicate content. Most importantly this will help for sites hosted on IIS server when re-direct are no possible. For more information on how to implement and what the tag can and can’t do head over to the post on the Google Webmasters Blog.