On one Web site, you can maneuver a digital image of a black man into a virtual noose. Another claims that Jews kill Christian babies and use their blood to make Passover matzo bread. On a third, you can hear former Ku Klux Klan leader David Duke spout invective over his online radio network. All three sites, and dozens of others like them, are blocked by the "HateFilter" online content filter developed by the Anti-Defamation League (ADL) in collaboration with CyberPatrol maker The Learning Co. The filter debuted here Wednesday during the ADL's 85th annual national convention. HateFilter represents an attempt to "counter hate speech with more speech," said Mark Edelman, the ADL's director of marketing, during a demonstration of HateFilter. The tool, which parents can buy for $29.95 (£18) from ADL's Web site and install on their home computers, redirects users from a selected list of racist Web sites back to the ADL site and explains why the sites are blocked. ADL officials stressed that parents will have to choose to install HateFilter, so its use will be voluntary, and said their aim is not to censor Web content but to give parents a way to keep youngsters from being duped into believing erroneous information on hate sites, such as Holocaust revisionist sites. Staff members will monitor the Web for new hate sites and changes in the location of existing sites, and HateFilter users will be provided with weekly updates, said Abraham Foxman, ADL national director, in an interview. Foxman said the group "understands the consequences of labelling people as racists and bigots," and said the sites ADL chooses to be blocked are judged by "the total content of the site, not just certain key words." Asked whether the Internet has given groups like ADL new weapons in the fight against racism, Foxman said the technology has been a mixed blessing. "If I had my choice, the price to pay is not worth it," he said, adding that racist site operators have learned to exploit sophisticated animation, music, and video to attract young users. Foxman acknowledged that the group could be open to criticism from free speech advocates, although he said the fact that its use will be voluntary might silence some critics. In the ADL's press release on the debut of HateFilter, attorney and First Amendment expert Floyd Abrams is quoted as saying "By providing parents with the opportunity to block sites containing hate speech in their home at the same time as the sites are fully available to the general public, the ADL acted in a manner that is fully consistent with the First Amendment." The product is available for a free seven-day trial on the ADL site. Got an opinion on this article? E-mail the editor.