We already have copyright laws that arm righteous copyright owners well enough to track down and sue violators. They have already been used to track down and sue violators and shut down sites that cater to them. Just today, MegaUpload was shut down by authorities in spite of their compliance in having a system to remove copyrighted materials. If we're shutting down sites with legal uses just for providing a service that's abused for illegal uses, we've already gone too far.
If we were to apply these concepts to crimes outside the internet, we would be permanently shutting down public roadways because they're used for transporting bootleg merchandise. We'd shut down all couriers for transporting without inspecting to verify authenticity and ownership. We'd evict countless legitimate businesses and demolish whole buildings, because a couple of tenants had been secretly using the space they rented for selling, storing, or packaging bootleg merchandise. If the bootleggers or customers leased cars or carried merchandise on a bus, train, boat, or airplane; the transit services would be shut down. (Lexi)