Google’s February 12th announcement of the new ‘rel=“canonical”’ tag as a simple solution to duplicate content woes sparked heated debate at SES London the following week.

Just five days after the announcement, presenters and attendees alike had already formed strongly opposing views on the new tag and its functionality. Some see it as a beneficial quick fix while others see it as a veil over bigger problems. Below is a rundown of the argument against the use of the new tag. But first, what exactly is the ‘rel=”canonical”’ tag?

Google’s ‘rel=”canonical”’ tag is used to combat duplicate content problems by allowing you to specify your preferred version of a URL. Basically, if you have a lot of URLs with similar content, the tag helps the search engine recognize one page as the original. The tag is also supported by Ask.com, Microsoft Live Search and Yahoo! Read all about it on Google’s Webmaster Blog.

Though SEO celebrity Rand Fishkin of SEOmoz calls the tag the “most important advancement in SEO practices since sitemaps”, not everyone is so enthusiastic. So what do some SEO experts have against this seemingly no-brainer solution?

Well, it’s not such a no-brainer. One expressed concern was that those without proper knowledge and training will use the tag incorrectly thus confusing the search engines more and ultimately hurting their ranking. If you plan to try it, check Rand’s tutorial blog first.

Other people have questioned the functionality of the tag. Google says that it will “honor strongly” the use of the rel=“canonical”, but what that means in execution no one is quite sure of yet.

Perhaps the strongest argument against the use of rel=“canonical” is that you should’ve done it right from the beginning rather than scrambling for quick fixes in the aftermath. However, if you have inherited a messy site or have an older, more established site with all kinds of URLs floating around, this tag may be the best option when you don’t know what else to do.

We see upsides and downsides to the tag. In the end, the decision to use it would vary based on a number of factors depending on the site and the situation. What do you think? Will you use the rel=“canonical” tag to fix your duplicate content problems? If not, what’s your solution?

Want to find out if you have a duplicate content issue? Enter your URL at copyscape.com to find out where your content has been copied.