I have an ecommerce site built using Magento and urgently need advice on best practice for handling multiple product categories (where products appear in more than one category on the site creating multiple URLs to the same page).
In April this year, based on advice from my SEO who felt that duplicate content issues were causing my rankings to be held back, I changed about 25% of the product categories to 'noindex, follow'. This has made organic traffic fall (obviously) as these pages fell out of Google's index. But, contrary to what I was hoping for, it didn't then improve rankings - not one iota, nothing - which was the ONLY reason why I did this. This has had a real negative impact on sales, so I'm starting to think this was actually an a terrible idea.
Should I change them back?
And to ask a wider question, what is best practice for this particular scenario?