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Hello all I'm currently getting back over 8000 crawl errors for duplicate content pages . Its a joomla site with virtuemart and 95% of the errors are for parameters in the url that the customer can use to filter products. Google is handling them fine under webmaster tools parameters but its pretty hard to find the other duplicate content issues in SEOMoz with all of these in the way. All of the problem parameters start with ?product_type_ Should i try and use the robot.txt to stop them from being crawled and if so what would be the best way to include them in the robot.txt Any help greatly appreciated.