This is where you can set specific variables to the 
apllication and session objects.

Whenever the application starts, this subroutine is fired, 
So you can place codes here that is specific to the 
application start event, say want to log when application 
starts.
Code in Session_Start will be executed every time a new 
session is started (e.g. a new user visits the site).

application_start is executed when the first time the 
application get executed.This is useful to findout total no 
of users visted in that website and etc.
Session_start will get executed when each unique user enter 
in to the application here u can access session specific 
values,username ,pwd etc.

This is where you can set the specific variables for the 
Application and Session objects.

Application_Start is fired when the application loads first 
time. Here use static data only.Do not use instance data 
this is recommended.


Session_Start is fired when a user enters in to the 
application.(when he requests first time.)