Possible Duplicate:
Content appearing under multiple categories; anything I can do to prevent duplicate penalty?
What is the best practice to display a product that may be in several categories without producing duplicate content as far as search engines are concerned?
In the past I have used a default category for each product so only one url is ever displayed for each product, but this is not a nice user experience if for example a product is listed in: maincategory A, subcategory B and also maincategory B, subcategory D and the user navigates through B > D to the product and the page url is displayed as website/A/B/product - the user may have lost the subcategory they came from initially.
Is it really necessary to remove the duplicate url for SER purposes? Or will the SE pick the most appropriate one to list?
