Hi Harini,
Managed or unmanaged is related to if an application server is controlled by a node agent and is part of a cell.
The applications don't know if they are in a managed or unmanaged node. No matter how is the node.
In your blog post Surya's answered perfectly:
www.websphereusergroup.org/harini/blog/2... Nodes can be managed or unmanaged. An unmanaged node does not have a node agent or administrative agent to manage its servers, whereas a managed node does. Both application servers and supported web servers can be on unmanaged or managed nodes. A stand-alone application server is an unmanaged node. The application server node becomes a managed node when it is either federated into a cell or registered with an administrative agent. When you create a managed node by federating the application server node into a deployment manager cell, a node agent is automatically created. The node agent process manages the application server configurations and servers on the node. The administrative agent is a single interface that monitors and controls one or more application server nodes so that you can use the application servers only to run your applications. Using a single interface reduces the overhead of running administrative services in every application server. Hope this helps.
regards