How to make child porn blocks safe for the Internet

Last week, an obscure quasi-non-govermental agency called the Internet Watch Foundation was catapaulted into the spotlight on the news that they'd classed an image from Wikipedia as child pornography and that as a result, the page was blocked for 95% of the internet users in Britain. That's because the IWF is charged with creating a secret blacklist of child-porn URLs that it distributes to subscribed ISPs, who then block those links for their users.