In Contrast to Social Media sites being a risk to children, I think it also may be of benefit to exposing possible criminal activity or useful in gathering evidence in cases of child neglect and abuse. Parental activity can be monitored. Possible alcohol, drug use, and other such activities can be often detected within parents accounts that may be invaluable insight to their parental care or non-care in regard to children's welfare.
There are two aspects to every issue. Using the social media as a tool to protect children is a viewpoint that was not explored in this publication, but might be very valuable evidence to actually protect minors.