I just got this e-mail from Microsoft:
Dear parent or guardian:
According to the birth date provided for your child’s Microsoft online account, XXXXX is now 13 years old. You are therefore no longer able to manage permissions for the XXXXX account through Account Services, and your child may create a new account without your permission.
United States law requires websites and services to obtain parental permission to collect, use, or share personal information from children under 13. Because this child is now 13, you can no longer manage permission for this child for Microsoft online services.
For information about how Microsoft collects and uses personal information, please review the Privacy Statement at http://g.msn.com/2privacy/enus.
For ways you can help protect your children online, see the Online Safety Guide at http://join.msn.com/?page=features/parental&pgmarket=en-us&ST=1.
Thank you for using Microsoft online services.
Microsoft Customer Support
Please do not reply to this message, which was sent from an unmonitored e-mail address. Mail sent to this address will not be answered.
Very odd choice in wording.