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I had the same problem on http://www.tokenrock.com because I was doing a lot of URL Rewriting, it's a CMS system I wrote, but the same issue apply. I went from 7000+ errors according to SEOMoz, and I'm down to 700. Here's a few things I did: Use canonicals on everything you possibly can. Redirect 301 the items in the SERPS that are identical. I'm not familiar with Magento to help you work though that side of it. Having a link like: domainname/leather-chairs-244-16-price-1.html would work much better. The ones you have listed are because somehow somewhere you (the site) have a link to it. Unfortunately some of the CMS's are written by developers who don't fully understand SEO and why the ? is a bad thing.