Trees or Tables? LDAP or RDBMS?
By pelegri on Feb 11, 2007
I believe OpenDS will turn out to be a very popular project. The team has been taking a soft-launch approach but they actually are already in pretty good shape - check the OpenDS tag for some earlier news.
Trey recently wrote a blog entry contrasting LDAP with RMDBS. In part it boils down to whether your application data is better modeled by Trees or Tables. Check out Trey's blog. You may want to also check the LDAP page at Wikipedia, and the latest standard spec, LDAPv3, at IETF