The .Net Remoting framework supports Server and Client activation of Remote Objects. Before an Object instance of a Remotable type can be accessed, it must be created and initialized by Activation process. There are commonly two types of activation modes : Server Activation and Client Activation mode. Server activation is normally used when a Remote objects is not required to maintain any state between method calls. Client Activated objects are instantiated from the client, and the client manages the lifetime of the Remote Object by using a lease-based system provided for that purpose.
SingleCall Objects and Singleton Objects belong to Server Activation mode. For SingleCall objects the server will create a single object, execute the method, and destroy the object again. On the other hand with Singleton mode only one object is created at all. Singleton objects can be used to share information between multiple clients. The real distinction between Client Activated and Server Activated object is that a server-activated object is not really created when a client instantiates it. Instead, it is created as needed.