Facebook, Microsoft, Twitter and YouTube are joining forces to prevent violent and extremist content being shared on their sites.
The four companies announced plans to create a digital database which will identify the “most extreme and egregious terrorist images and videos” by hashing them with a ‘digital fingerprint’.
The unique algorithms mean that if an offensive video is flagged up on Twitter, for example, they can ensure the same material does not appear later on Facebook or Youtube.
A joint statement said: “There is no place for content that promotes terrorism on our hosted consumer services.
“When alerted, we take swift action against this kind of content in accordance with our respective policies.
“Each company will continue to apply its own policies and definitions of terrorist content when deciding whether to remove content when a match to a shared hash is found.”
In time, the database will be made available to other websites who wish to monitor this kind of activity.