LDAP: What it is?

I just configure my first LDAP server installation on Linux machine. A Directory service running on port no 389, that can be used for Authentication, Directory listing of person and Organization resources like computer, printer etc. is known as LDAP (Lightweight Directory Access Protocal). Don't know whats light in it :o). I used OpenLdap server to configure my service, So far able to add Linux based user to LDap server and can access the data from LAN machine through command line. Will start more work on it ... seems a good application all together. Sumit Gupta