Many shop owners need duplicate categories, which is customer friendly. But what is the best way to avoid duplicate content (product) pages for the search engines?
If you have a product that is assigned to i.e. three different categories and also make use of plugins like 'Featured Products' and 'Top-Ten Products' you already might have five different URLs pointing to the same product page.
What happens if i.e. Google decides to pick the 'Featured Product' URL as the most important and drops the others from the serps? In this case the product might drop completely out of the Google index for a while, if you change the featured product.
One possibilty would be an option to hide categories from displaying in the URLs.
Another possibility would be an option to add a canonical tag (see link below).http://www.google.com/support/webmasters/bin/answer.py?answer=139394
...any more bright ideas?