It is the Children's Online Privacy Protection Act, a society dedicated to making the internet safer for kids. The forums registers whether you're registered with COPPA or not.
If you make your own account on the forums and your under the age of 13, then you will receive an email that requests a parent's signature to join. That's how you would get the COPPA. If an adult (or over the age of 13) makes an account, or an account for you, then there is no extra email and you will not have the COPPA.
