X.500 was tried and deemed too complex/unworkable and has since been mostly abandoned. (Who remembers X.500 DNs leaking out as e-mail addresses some twenty yea

X.500 was tried and deemed too complex/unworkable and has since been mostly abandoned. (Who remembers X.500 DNs leaking out as e-mail addresses some twenty years ago?) The idea of a directory service is a good one, so we ended up with LDAP and AD.