If it wins then EBay could have a bit of a problem, because it is impossible to tell if the goods that its customers are flogging are real.
Currently EBay's policy is to allow the sale of knock-offs until it gets a complaint from someone who owns the trademark or copyright.
However, if a normal punter complains that they have spotted an illegal sale, Ebay apparently refuses to notice, sticks its hands in its ears and sings loudly.
The New York Times cites the case of one woman who got her money back when she realised that her Weiss piece of jewellery was a knock off, but Ebay refused to remove similar items. Tiffany's accuses eBay of "charges hundreds of thousands of dollars in fees" for counterfeit sales.
Apparently in 2004, Tiffany bought 200 items from eBay. Three out of four pieces were fakes, according to the New York Times . ยต