Naven
Glossary
Member directory
A searchable list of a platform's users.
It is how you find your friend, and it is how a stranger finds your child. Every directory is both at once, and the usual mitigations — you must know the exact username, you can opt out, you can be invisible to non-contacts — are attempts to keep the first without the second.
No directory at all is the strongest version, at the cost of making legitimate discovery harder.
Where Naven stands
Naven has no name directory. You are reached by an email address or exact username somebody already has, and name matching only searches conversations you are already in.