Never volunteer on a mailing list to give somebody a quick introduction into OpenLDAP! You could end up with twenty people listening to a presentation about LDAP in general which you have to come up with off the top of your head.
It happened to me yesterday and fortunately went quite well. I had a bit help from the audience and a lot of people realized soon that they already encountered LDAP as Active Directory.
Despite being somewhat unprepared I enjoyed giving that lecture. And I’m foolish enough to believe that the audience enjoyed it as well. 🙂