The Benefits of LDAP/X.500 Directories. Information on people, computer resources, and access privileges can be put in many types of data stores. Quite often, it's put in a data store accessed through LDAP or X.500 protocols.

The benefits of using LDAP- or X.500-accessible directories are:

Irrespective of the choice of an X.500 or non-X.500 back end, LDAP is the most common form of access. X.500 DAP is sometimes required, particularly for high security where signed operations are desirable (not available in LDAP) ... David Ferris, With thanks to Isode's Steve Kille and Persistent Systems' Sameer Karmarkar