The organization's main exhibit was "Ethnic Cleansing," a computer game sold by Resistance Records, a small underground label that specializes in bands spouting racist and Nazi messages.
The game requires players to wander through urban streets and subway tunnels and to attack African-American, Hispanic and Jewish characters. Besides offensive racial stereotypes, the game includes repeated racist images and audio content.
Later in the week, the copyright holder of the software tools used to create the game disavowed any involvement with "Ethnic Cleansing."
While there are no indications "Ethnic Cleansing" or more primitive games such as "Aryan 3" have spread beyond a marginal following of racists and neo-Nazis, Abraham Foxman, national director of the ADL, said it was disturbing to see the emergence of a "seductive" new vehicle for disseminating racist beliefs.
Initially, "Ethnic Cleansing" looks little different from popular shooting games such as "Quake." The sophisticated graphics of the game could attract players who wouldn't realize the true nature of the material until they were well into the game, Foxman said.
"It piggybacks on something that is very legitimate and popular and perverts it," he said. "It can attract people who aren't necessarily going to look for this kind of material."
Foxman said the ADL's main goal was to raise awareness before such games proliferate. The Resistance Records Web site states that the developers of "Ethnic Cleansing" are working on a new game based on "The Turner Diaries," the anti-government novel that inspired Oklahoma City bomber Timothy McVeigh.
"Our hope is that we can alert the general public that something like this can come into the home," Foxman said.
Representatives for Resistance Records did not return a request for comment.
Foxman said the ADL was also looking into the type of software that allows amateur programmers to create such games. "Ethnic Cleansing" was created with Genesis 3D, a collection of graphics tools freely available under an open-source license.
"We think you have a certain responsibility...to make sure your patents aren't perverted for reasons of hate," Foxman said.
The Genesis 3D copyright was acquired by software developer WildTangent as part of its 1999 acquisition of Eclipse Entertainment. The software has been distributed under an open-source license since that time, however, and Wild Tangent has had no involvement with it, Wild Tangent CEO Alex St. John said in a statement.
"We have no more association with the content that is produced on this engine than Microsoft has with the content posted on the Internet that uses Internet Explorer or a CD manufacturer has with the content distributed on their media," he said. "We at WildTangent regret any association, no matter how distant, with the game engine highlighted in the Anti-Defamation League report and certainly do not support nor condone the use of our technologies to sponsor hatred or to recruit individuals to hate groups."
Brian Marcus, a researcher at the ADL's Internet monitoring unit and author of the report, acknowledged the difficulty of using software licensing restrictions to limit hate speech, especially among the largely self-policing open-source community.
"That's the nature of the open-source community," he said. "You're putting it out there for the good of the community, but if someone wants to misuse it, it's there for them as well."