Each Classlist site provides a secure closed platform unique to your school.
Access to each year group's data is restricted to other parents in the same year group at the same school. By default only parents with children in the same year group can see each other's personal information, although anyone can message a parent in another year group through the private message feature (ie without using a parent's personal details).
You can also specify more particularly who sees what information in your account's privacy settings, accessed from your profile. The only things that must be visible to everyone in your class as a minimum are your name and the name of your child, to enable other parents to identify you.
Your School Ambassador/s, School Staff Admin (if you have any) and your Class Admin member/s will be able to view the data you submitted upon registration, but this is purely for authentication purposes.