I am working in Magento to build out a large e-commerce site with several thousand products. It's a great platform, but I have run into the issue of what it does to URLs when you put a product into multiple categories. Basically, "a book" in two categories would make two URLs for one product: 1) /books/a-book 2) author-name/a-book So, I need to come up with a solution for this. It seems I have two options: Found this from a Magento SEO article: 'Magento gives you the ability to add the name of categories to path for product URL's. Because Magento doesn't support this functionality very well - it creates duplicate content issues - it is a very good idea to disable this. To do this, go to System => Configuration => Catalog => Search Engine Optimization and set "Use categories path for product URL's to "no".' This would solve the issues and be a quick fix, but I think it's a double edged sword, because then we lose the SEO value of our well named categories being in the URL. Use Canonical tags. To be fair, I'm not even sure this is possible. Even though it is creating different URLs and, thus, poses a risk of "duplicate content" being crawled, there really is only one page on the admin side. So, I can't go to all of the "duplicate" pages and put a canonical tag, because those duplicate pages don't really exist on the back-end. Does that make sense? After typing this out, it seems like the best thing to do probably will be to just turn off categories in the URL from the admin side. However, I'd still love any input from the community on this. Thanks!