Duplicate content is a huge problem on the web. Search engines have a hard time determining relevancy with duplicate content, and consequently penalize sites for it. Google, Yahoo! and MSN announced that this new canonical url tag can be inserted directly into an HTML header, which tells search engines to treat multiple url’s within the same domain that have similar or duplicate content as one url. This exciting new tag prevents site owners from being dinged by search engines and experiencing lower rankings and traffic losses due to multiple url’s having the same content. The Canonical URL Tag is useful for a variety of scenarios: •    If your category url’s creates multiple versions of the same page. For example: www.colors.com/yellow-color?color=yellow •    If a session ID creates duplicate content. For example: www.colors.com/yellow-color?SESSID=012 •    If your print-only url’s create several versions of the same page. For example: www.colors.com/print/yellow-color SEO professionals can help you determine whether you need this tag and where to apply it. Search engines will now be able to identify multiple url’s with duplicate content and decide what to include and exclude while indexing. When asked if this canonical tag was a hint or directive, Google said “It’s a hint we honor strongly. We’ll take your presence into account, in conjuncture with other signals, when calculating the most relevant page to display in search results.” Google, Yahoo and MSN will also take into account slight differences if the content is not an exact duplication, for example: slight differences in the sort order of products. They also specified that even a redirect url can be tagged with the canonical tag. Also, they stressed that the canonical tag cannot point to an entirely different domain, that it must be on the same domain or subdomains. This breakthrough canonical tag is an exciting new tool in the web world because it helps deal with problems associated with duplicate content, and allows search engines to index sites more thoroughly.