Governments are urging Facebook, Twitter, and Google to more aggressively remove extremist content, in the hopes of reducing the terrorist group’s influence. But the companies’ self-moderation systems have struggled to keep pace, and terrorist material continues to spread online. The algorithm, called eGLYPH, was announced in June by the Counter Extremism Project (CEP), a New York-based nonprofit organization that tracks extremist groups. eGLYPH uses so-called “hashing” technology to assign a unique fingerprint to images, videos, and audio that have already been flagged as extremist, and automatically removes any versions that have been uploaded to a social network. It will also automatically delete other versions as soon as users attempt to upload them.