Social media platforms have a recurring problem. They want to support free speech, but in doing so, they don't want to support hate speech or terrorist messaging. Recently, however, Facebook and YouTube have been stepping up their efforts to combat this type of content, and they're doing it in an interesting way. Facebook and YouTube are taking down Islamic State videos using the same technology they use to automatically remove copyrighted material from their sites, The Guardian reports. What these companies are doing is the equivalent of digital fingerprinting: Each video uploaded to the site has a unique ID (called a hash). The hash is created based on various factors, such as analysis of key frames, and the predominant colors in the video. If someone tries to upload copyrighted content, all these video services have to do is compare that video's hash with that of its list of hashes that aren't allowed. If it matches, it can't be uploaded. What this means for terrorist and hate groups is that once such a video has been identified, that hash can be banned, essentially, and anyone else trying to upload that same video won't be able to. This process is reportedly entirely automated. While this method doesn't prevent entirely new videos from being uploaded in the first place, it does help keep duplicate videos from proliferating — and that's one less thing Facebook and YouTube users (and site moderators) have to worry about.