(CNN) -- May 20: Massachusetts, a brother and sister are snatched. A truck driver sees a vehicle that the suspected kidnapper is driving and calls police, who find the kids inside, under blankets and pillows. They're safe. The children's father is arrested.
May 22: A car with a 1-year-old girl inside is stolen near a Georgia day care. A security camera image shows a suspect getting into a vehicle and driving away. Police get a call from a resident because the suspect's car has been parked on a nearby street all night. The child is rescued.
July 1: An Ohio boy is believed to have been abducted by his father, who has a troubled history, and law enforcement officials are afraid the boy will be harmed. A group of friends at a diner spot the car driven by the alleged abductor and call 911. The man is arrested and the kid is safe.
The National Center for Missing & Exploited Children, which documents these "success stories," says they would never have happened without Amber Alerts being issued in each instance.
And though these cases didn't get the same national attention as the search for San Diego teenager Hannah Anderson, they are among hundreds that demonstrate why the program is critical to saving children's lives, said Robert Hoever, a director of special operations for the center.
Between the program's inception in 1996 and July of this year, at least 656 children have been rescued because citizens saw or heard an Amber Alert, according to the center, which works with law enforcement, broadcasters and federal authorities on the nationwide program.
Hoever defined "success stories" as verified abduction reports in which children are recovered safely.
Of the 2,064 children who were the focus of Amber Alerts between 2005 and 2012 (the years for which the center has complete figures on the number of alerts) 394 were rescued. The vast majority of those cases -- 2,030 -- were resolved, though "resolved" can have different meanings. It could be that a case, once investigated, is determined to be falsely reported to police. And, some cases are still ongoing.
But investigating a case takes time, and actions taken in the first hours after a child disappears are crucial, experts say.
Why Hannah's case was unusual
"Hannah's case stood out because it has other tragedies -- the killing of her mother and brother, the nationwide manhunt. But it's also very important because it was just textbook how this program should be used," Hoever said. "You had the combination of a new technology, with very careful moves by investigators to broaden the sending of the Amber Alerts as new leads came in."
On August 4, a 10-second, high-pitched tone rang on thousands of mobile phones across the West Coast -- the first use of a new wireless alert system.
The alert announced that authorities in Southern California were looking for 16-year-old Hannah Anderson and her 8-year-old brother Ethan. The children's grandmother had reported them missing, the same day that James DiMaggio's home burned down. The children's father, who gave television interviews in the hope of keeping his daughter's case in the spotlight, would later describe DiMaggio as a onetime family friend.
Inside DiMaggio's charred house were found the remains of the children's mother, Christina Anderson, and a body that would later be identified as Ethan's.
Hannah had last been seen at cheerleading practice near her San Diego home August 3.
When authorities heard that DiMaggio might be heading into Nevada, the alerts were expanded to that state, Hoever said. When new clues suggested DiMaggio might be entering Oregon and Washington state, the alerts were activated there. Ultimately, when Idaho became a possible landing spot for the suspected criminal, cell phones buzzed there, too.
The teenager's abduction was the first time the new, federally administered Wireless Emergency Alerts program was issued statewide, California Highway Patrol spokesman Erin Komatsubara told HLN.
"The wireless program was also used in five states at one time," Hoever said. "That is the largest use of the program I've seen."
Riders who made a difference
The Idaho horseback riders who spotted Hannah and DiMaggio in rugged terrain sensed something was wrong. The teenager and the man were inappropriately dressed for the wilderness and their tent was pitched on a mountain like someone inexperienced in camping might do.
But the horseback riders were cautious, exchanging a few words with DiMaggio. But when they got home, they saw Hannah's Amber Alert on television.
That made all the difference, they believe.
"People need to be aware and observant," rider Mary Young said on CNN this week. "Otherwise we would have missed turning in that information."
The riders contacted Idaho State Police, and their tip over the weekend sent FBI agents swarming to the camping spot outside Cascade, in central Idaho.
Hannah was rescued. DiMaggio died in a confrontation with an FBI agent.
Who was Amber?
Amber stands for "America's Missing: Broadcast Emergency Response," but its namesake was Amber Hagerman, a 9-year-old Texas girl who was last seen alive riding her bike in a parking lot in January 1996, according to the National Center for Missing & Exploited Children.
A witness said a man with a black, flatbed truck was talking to the girl and snatched her bicycle.
Four days later, Hagerman's body was found in a creek eight miles from her home, according to the National Center for Missing & Exploited Children.
Dallas and Fort Worth residents were heartbroken. One resident wrote a letter to a radio station suggesting that the Emergency Alert System be used to notify the public when a child is reported abducted.
The first success of the program came after a November 1998 kidnapping, Hoever said.
A motorist heard an Amber Alert on the radio after an infant was abducted from an Arlington, Texas, apartment complex.
The motorist "called into law enforcement saying, 'I'm riding next to the car that you're looking for!' He was almost ecstatic, saying 'I can see the baby next to her!'" Hoever said.
The police tracked down the vehicle and rescued the baby.