Facebook and Google, two of the biggest hosts of videos on the internet, have quietly started to use automated processes in a bid to eradicate extremist content from their platforms.

Facebook and Google-owned YouTube are among the websites that have deployed systems to prevent the uploading of videos by the Islamic State and other such material, according to sources. The systems are also capable of immediately taking down the videos if for some reason they are are able to bypass the restrictions and are uploaded online.

The technology being used in targeting extremist content is the same one currently being used to seek and delete copies of copyright-protected videos from being uploaded to websites. The system detects so-called hashes, which are unique digital fingerprints that are assigned to videos. With a hash placed on the original video, all other videos with the same hash can be immediately removed.

This system would allow Facebook and Google to stop the spread of extremist videos, such as those which show the decapitation of hostages, by applying a hash on the original video. The limitation, however, is that newly uploaded videos will not be automatically blocked or removed.

However, both Facebook and Google have not discussed how exactly a certain video could be labeled as having extremist content. While a video showing a beheading will clearly fall under the category, where will the line be drawn between a passionate speech and a call for violence?

It is also unclear whether the companies will rely exclusively on the automated process to search for and delete extremist content, or whether the review process will have humans involved to assist in the selection of content to be kept and deleted.

Internet companies have largely supported governments in the suppression of the propagation of extremist videos, but they are also looking to not be liable for the content if the videos end up in their platforms. The political mood in the United States looks like there will be more pressure applied on tech companies to work on the issue, with President Barack Obama suggesting that online extremism could be the reason for the terrorist attack on an Orlando gay nightclub that left 49 people dead.

Another online platform, Twitter, has launched an all-out war against organizations such as ISIS which promote violent extremism. However, while the social media service has been trying its hardest to take down ISIS-related accounts, supporters have been faster in getting new accounts online.