There has been some recent discussion in the SEO community about whether Google and Bing have different rules for the use of the rel=”canonical” tag. Google has said it is fine to have self-referential canonical tags (ie. the rel=”canonical” tag specifies the same URL as the page you are on), whereas Bing indicates they’d prefer the canonical tag be left blank in that case.
The proper use of rel=”canonical” can be confusing at best, and can produce devastating results at worst. So what is an SEO to do?
First of all, realize that using rel=”canonical” isn’t necessary in many cases of duplicate content. The canonical tag is a great tool for extreme situations and enterprise-level sites, but on small to medium sized websites there are often other solutions.