Facebook, Microsoft, Twitter and YouTube said this week they will work together to remove terrorist videos and photos from their services.
The Web services providers intend to create a database that uses digital fingerprinting techniques to identify photos, videos and other images that can be used to promote terrorism. "Our companies will begin sharing hashes of the most extreme and egregious terrorist images and videos we have removed from our services -- content most likely to violate all of our respective companies’ content policies," they said in a joint blog post.
The move comes the same week that European officials reportedly said the companies weren't moving quickly enough to combat extremism.
In the U.S., unlike Europe, Web companies aren't required to censor their sites. While some people have attempted to sue Twitter, Facebook and other companies for allegedly encouraging terrorism, those efforts have failed in court.
Facebook and the other Web companies are spinning their move as one that will "further our shared objective to prevent the spread of terrorist content online while respecting human rights."
But some observers warn that the new policing efforts could create a precedent that can be used to censor a wide range of material.
"These companies will undoubtedly face substantial pressure from governments and private actors across the globe to expand the scope of the database and include additional content in it," the digital rights group Center for Democracy & Technology writes today in a blog post.
The group also warns against the prospect that, acting together, the four companies will together be able to wield new power to purge information from the Web.
"If an image or video can reliably be suppressed from all the major social media platforms at once, what will happen to people’s ability to find this material to inform news, political debate, academic research, policy discussions, art, literature, or any of the myriad other wholly legitimate reasons to post and access even horrific examples of terrorist propaganda?" the CDT asks. "Proposals such as this one that focus on smoothing the way for coordinated censorship create substantial dangers for the future of the information society."