Actually this rel=conical tag is used when you have same content on more then one pages of your site,this tag will then directs the google bot to choose the page you want to indexed by google among all those pages..
January 14, 2012, 2:56 pm
Upvotes by No One
A canonical page is the preferred version of a set of pages with highly similar content.
It's common for a site to have several pages listing the same set of products. For example, one page might display products sorted in alphabetical order, while other pages display the same products listed by price or by rating. For example: