I was also wondering how popular LDAP is? If you are thinking of using Hologram, or can benefit from it, would you please comment and mention if you already use LDAP or some other alternative?
But then again, if your org is large enough to have LDAP set up, getting LDAP policies changed to support something like hologram would generally be a non-starter in my experience.
In large enterprises, the LDAP service is a core security service that is rarely if ever modified except for periodic maintenance and upgrades.
Messing up the LDAP service for any reason will compromise or disable all authentication company-wide. It's not fun when the CEO comes over and says that his wifi and email logins aren't working anymore...