Comment by ElectroBuffoon

Or parents could set accounts to "child" and every service send the proper tags so the programs deny access locally. No third parties involved.

PICS https://en.wikipedia.org/wiki/Platform_for_Internet_Content_...

POWDER https://en.wikipedia.org/wiki/Protocol_for_Web_Description_R...

ASACP/RTA https://en.wikipedia.org/wiki/Association_of_Sites_Advocatin...