In the Dallas-Ft. Worth metroplex, we've got the "Amber plan," named after a little girl abducted four years ago and killed.
When a missing child is reported, police notify a central number which alerts every radio and TV station in the area. An alert is issued.
Some of these are false alarms (the kid wandered away), but many are legitimate, and the plan has resulted in 12 or 13 recoveries of children, alive, directly due to the efforts of the community.
Most abductions are by a family member, at least here.
I understand that the Amber plan has migrated to other cities.