I'm going to presume from your answer that OpenLDAP is not sufficient then? Certainly Linux systems can use LDAP.

- It's far from consensus that a puppy-like system is the best way to manage the settings of all your computers, including desktops. Linux has plenty of other tools for managing multiple computers, and almost nobody uses only one.

- Really, what was MS thinking when they joined email configuration with the desktop settings management? (And ntp, dhcp, and etc?) AD imposes a lot of restriction on how one must organize his services, and just a tiny minority would be content with something like that on Linux.

- There are plenty of yellow pages solutions that people like more than LDAP.

Selling Exchange licences, what else?

> AD imposes a lot of restriction on how one must organize his services

Preventing machine-profile creep is a big concern for me. Every different kind of machine we deploy is one more different configuration we need to manage.

I think the operative word here is "can." Active Directory allows you to actively reject machines from your network that are not part of the Domain and it can prevent you from extricating a machine from the Domain to circumvent restrictions imposed upon the machine, the user, the location, or any other myriad of configurable factors.

It would surprise me if there was something you couldn't do to on a nix machine that you could do with Active Directory on a Windows based PC but the time and maintenance involved are in no way proportional. The full featured and easy to use tool-chain was what made Microsoft great, and they lost that with overly complicated systems in the 2000s but they seem to be getting back on the right path with Powershell and their Core Server administration tools.

Additionally Active Directory is an LDAP provider so it's relatively easy to integrate nix machines into an AD environment.