Some of the biggest names in tech have concocted a plan to combat the spread of terrorist content online together. Facebook, Microsoft, Twitter and Alphabet-owned YouTube are creating a shared database of "hashes" for any terror-related content they remove from their services. Hashes are unique code identifiers associated with each photo and video that computers can use for identification. For instance, if Facebook spots a new recruitment or (heaven forbid) beheading video on its website, the social network will give it a hash before and upload it to the database. The websites won't automatically purge photos and videos in the database, though -- each service will still review and remove them on their own.