I thought they might use the British CleanFeed system but apparently the companies have agreed to shut down access to Usenet newsgroups that traffic in pornographic images of children. The US ISPs are a bit slow on this as the UK ISPs have been blocking access to similar Usenet newsgroups since 1996…

3 Net Providers Will Block Sites With Child Sex: “Verizon, Sprint and Time Warner Cable have agreed to block access to Web sites that spread child pornography.

(Via NYT > Technology.)