My point is, Facebook doesn't allow minors under 13 to register. You're right - those are their terms of service, which are likely based on COPPA (guessing that FB doesn't want to deal with the hassle of the requirements). Regardless, since Facebook doesn't allow it, we should not allow or encourage Scouts to violate those terms of service (a Scout is trustworthy and obedient, after all). So, if we are living by the Scout Law, then Facebook isn't an option for 10 1/2 through 12 year olds in a Troop. That was all I was trying to point out.
The issue with Facebook (Google+ and the other social sites) is that Scouts under 13 can't legally use them (see here for Facebook: https://www.facebook.com/help/?faq=210644045634222). This is to deal with COPPA, which restricts what websites can do with information for youth under 13. Out of our troop of 110 boys, we have a fairly large number of boys who wouldn't be able to use the public sites. This makes it a non-starter for us. As I understand it, you can allow registration on a private website for your unit and not run afoul of the COPPA requirements. As someone who maintain