LDAP is actually a protocol, just like http://
So the CFML tags/functions are a way of creating LDAP protocol requests.
ldap://xxxxxxxx
LDAP works with corporate directories like MS Active Directory.
Note: Active Directory is NOT the only one - but it is certainly the most common / well known.
It is also useful to think of Corporate directories like a Database.
You will often hear statements like;
"do a lookup, via LDAP" or
"Use an LDAP query to find out the group membership of a user".
or "use an LDAP query to authenticate a username and password".
So the mindset for LDAP is very SQL-like.
In fact if you think of Active directory as a database and LDAP as a special flavour of SQL - then you really can't go wrong.