From their website:
The Ontario AMBER Alert is a warning system that quickly alerts the public of abducted children who are in imminent danger.
The participation of the public is essential to the success of AMBER Alert. The information you provide to police may help an abducted child before it is too late.
We can take action together to protect and safely recover abducted children.
From the CTV.ca website:
OPP say information posted on the social networking website could reach millions of users who can help in the search for abducted children.
Authorities hope Canada's 15 million Facebook users, including seven million in Ontario, can help them in the first crucial three to five hours after a child is abducted.