Chapter2

What are the difference between ASP.NET 2.0 & ASP.NET 3.5?

The sharepoint root is located at:

C:\program files\common files\microsoft shared\web server extensions\(12 or 14)

All sharepoint web applications are created at:

c:\Inetpub\wwwroot\wss\VirtualDirectories

SP2010 removes some of the standard HttpModules like
Anonymous Identification
File Authorization
ASP.NET profiles
Session
WebDAV

So you cant use ASP.NET session state in your SP code. SP code has to be stateless.