From the Tween-Us blog – information on Instagram, the hugely popular photo-sharing app that is now owned by Facebook.
I share this with one caveat, and it’s a big one: People who sign up for Instagram accounts are, legally, supposed to be at least 13 years old. Which means 4th, 5th, and 6th graders are not supposed to be on Instagram, and those who are have lied about their ages to get an account. Maybe someday the law (COPPA) will change. It certainly doesn’t seem to reflect the realities of the current digital landscape. But until it changes, it’s the law; we and our kids should follow it.
http://www.chicagonow.com/tween-us/2014/01/kids-safe-instagram-parents-need-to-know/
The article also references Socially Active, which is a tool for monitoring your kid's online presence.