As the biggest social network in the world, Facebook is privy to information about countless people's moods and feelings at any given moment. The company is now giving users a way to reach out to friends they suspect are in danger of harming themselves, based on their Facebook activity.
When a user flags a post that seems concerning, Facebook will review it and offer suicide prevention materials and advice on how to help the person in question. The person who wrote the post will receive similar information, as well.
In a sense, this is an extension of Facebook's Safety Check feature, but there's a chance some people may see it as yet another breach of their privacy—or as further proof that Facebook is always watching.