Hello, So I have searched the Q & A , Google, the zen cart forum and at this point I am looking for some one to give a concrete answer on what I should do.  There is a lot of different opinions on " rel=canonical" and how to apply it , since there are many other variable in place. I have a zen cart site.  I am using the latest 1.3.9 version.  The default setting ( seem to me) uses the  rel=canonical to point back to the specific link product or category respectively. Most of the time I have two scenarios. 1. Main category --->  Sub category----> Product 2. Main Category----> Product I'll give an example http://www.perfectindesign.com/awards ---main category http://www.perfectindesign.com/awards/acrylic-awards sub category http://www.perfectindesign.com/awards/acrylic-awards/slanted-award  product (this example has three sub categories with maybe 12 products in one 4 in the second and 5 in the third) From looking at the source code for each url it the rel=canonical just points back to its own url. I want to avoid competing against my self, for the example above keyword "acrylic awards" so should the use of the re=canonical be changes site wide to have products point back to sub categories when they exist and have products point back to main categories when no sub categories exist? I am very new to seo, specifically eCommerce seo.   If you have experience and have done this to a site you manage for a client or your own please advise how to proceed. Also if I'm missing some thing that will give me a better understanding of the bigger seo picture that would be great. Thanks, Yevgeny