Definition - ADAM or Active Directory Application mode is a mode of active directory provided by Microsoft in Windows Server operating systems to allow active directory enabled applications to work with the current Active Directory infrastructure without modifying AD schema or without storing data in Active Directory database.
Supporting Operating Systems - Windows Server 2003 -Family (except Windows 2003 web server) and Windows XP Operating System.
For Beginners: -Lets start the journey towards active directory application mode. (Before starting this tutorial it is assumed that the reader is having some knowledge of active directory).
Suppose your organization is running a domain example.com. Your company decides to implement a new application that will use active directory as the directory service and database. You tested that application and still you are not convinced about many features of that application. But still deploying that application is necessary.
Now the role of ADAM begins. You implement ADAM on a server named=appserver1 which is not connected to your domain example.com. Then you install the third party application your organization needs. The application which needs active directory as its directory service and database will now access the ADAM roll on appserver1 which will act as a Active Directory Server for the application.
Conclusion - Because you were not convinced about the new application but you wanted to deploy it , providing access to active directory, you actually deployed the application in such a way that it interacted with the ADAM roll on appserver1 as Active Directory database. With this kind of configuration your main Active Directory Database remains unaffected when deploying any such third party or Microsoft application.
