The first six hours in a missing child case are often called the "golden hours" -- a critical period holding the best odds of their safe return. With Facebook's new alert system, crucial information -- a description and a photo of the child, as well as their last known location -- should spread more quickly than before, giving police the best available intelligence. Facebook says the alerts will only be issued if a child's life is in danger, or they're believed to be at risk of serious harm -- so if you see one in your feed, you should give it your full attention. "While we of course hope that we don't have to use this system, this partnership with Facebook will make a huge difference in extending the number of eyes and ears on the ground when the worst happens," Jo Youle, CEO of Missing People said.