aleksl - 3:11 am on Mar 17, 2010 (gmt 0)

g1smd, but then you are missing a whole lot of situations with your single URL. What if a product naturally belongs to Widgets, Gadgets, and SuperGadgets on Sale categories?

With your single URL, you have no clue which particular section user is on.

And how would you display breadcrumbs for this product if categories are not inclusive? would you display as 3 separate breadcrumbs? sounds silly.

The world should NOT evolve around search engines in situation as this one. It is way more natural TO PEOPLE to have same product in different categories, and there should be a way to reflect that in your hierarchy. If SEs don't like that - tough luck, this is such a simple and COMMON example for them to follow and resolve, that I think they ought to figure it out by now.