3 tier acrhitecture in Microsoft.NET web applications

We know that nowadays the systems are designed as web applications. Every imaginable system is either converted or planned to be converted to a web app. In Microsoft .NET world the famous three tier architecture is translated like this.

• Front End (Web Application)


• Middle Tier (DLLs and/or the DLL which contains some ORM)


• Back End (SQL Server or Oracle, or MySQL)

To me, the middle tier is not actually the middle tier because regardless of how isolated the design is and how stateless the DLLs are, they execute in the context of a web server only and essentially a part of the web application.

My Questions:

1. 
   

   Is my observation and understanding correct that 3 tier arch is not really a 3 tier but a simple 2 tier arch?

   
   


2. 
   

   Is it correct to design the apps this way when there is no technical middle layer, even the applications that require heavy processing?

   
   


3. 
   

   Current is the only option for middle tier for a web app is a windows Service and nothing else?