Facebook automatically scans posts and chat logs for criminal activity, using big data processing techniques similar to those used in targeting advertising to determine the most vulnerable users, according to a new Reuters report that explores combating pedophilia in social media. The social network's scanning tools use factors such as mutual friends, past interaction, distance and age difference — alongside simple phrase searches — to flag potentially nefarious conversations for human moderators. They also rely on archives of previous conversations that are known to have led to sexual assaults, identifying patterns and searching for similar ones.