We have recently made a change to the site to comply with COPPA. In a nutshell, this change requires that any members under 13 have parental consent before participating on the site.
We are sure you have many questions about this, so please see our About COPPA page, as we answer a lot of questions you may have there. If, after reading this, you still have questions, post them on the ACC COPPA Compliance Q&A sticky thread.
Animal Crossing: The other oxygen.