This question was asked and answered about a year ago on this list,
but I am hoping the answer may have changed over time....  ;-)

My understanding is that LISTSERV 1.8d has built-in DBMS support
for two main functions:  1) as a data store for list membership
information, and 2) as a back-end for ad hoc mail-merge jobs.

Both of these functions, and especially the latter, would be
tasks well-suited for an LDAP-based directory service.  In the
first case, the list membership information could be stored as
attributes within person and/or group directory entries, allowing
for dynamic updates of e-mail addresses, full names, etc., based
on current directory data.  In the second case, LDAP search
filters (queries) could be utilized to dynamically generate
DISTRIBUTE jobs for mail-merge and mass-mailing applications.  An
example of this at a university would be to send e-mail to all
current sophomore students with an English major and a 3.5 GPA
or higher (assuming this information is stored in the directory).

LDAP-based directories, utilities, and interfaces are now widely
available, and many organizations already provide this service
to their customers (internal and/or external) for other purposes,
such as online phone book applications.  If LISTSERV could take
advantage of this capability, instead of requiring a conventional
RDBMS application to be created, it would provide a great benefit
to its users.  Please consider this a request for such a feature.

Thanks,
Alan

--
Alan S. Dobkin, Operating Systems Analyst
Windows NT Group, Enterprise Systems Support
Information Technology Division, Emory University