OK guys ! I am answering myself..lol
If you are familiar with the Session object, you know already that data stored in session is not permanent and data stored is usually only available to a specific user.
The Application object stores data that is shared across the application and not for a specific user. Internally the values of both the Session and Application objects are stored in a key/value pair (HashTable).
All data stored in Application in stored 'in process', meaning if you restart your application all data in lost