Programming Microsoft ASP.NET 2.0 Core Reference

As of ASP.NET 2.0, there are four possibilities for working with the session state. The session state can be stored locally in the ASP.NET worker process; the session state can be maintained in a remote process; the session state can be managed by SQL Server and stored in an ad hoc database table. Finally, a fourth option is added in ASP.NET 2.0 and allows you to store the sessions in a custom component.

In ASP.NET 2.0, the session-state subsystem was refactored to allow developers to replace most of the bits and pieces of functionality a characteristic that is often referred to as session-state pluggability.

By default, the view state is enabled for all server controls; however, this doesn't mean that you absolutely need it all the time and for all controls. The use of the view-state feature should be carefully monitored because it can hinder your code and unduly bloat your pages.

In ASP.NET 2.0, the size of the view state is significantly reduced as a result of a new binary serialization format.

The contents of the view state have been split into two states: classic view state and control state. Unlike the classic view state, the control state can't be disabled programmatically and is considered a sort of private view state for a control.