Here in the UK an Internet filter designed to block child porn been accessible from within the country and most ISP’s signed up to use this back in June 2004.
Great in theory, but the problem with a nationwide nanny filter like this is it blocks the wrong stuff and the people it’s meant to stop just get round it by using proxies. Over the weekend a story can out saying just that. The Wikipedia page for Scorpions album Virgin Killer was blocked by the great firewall because of the album artwork displayed.