ASP.NET MVC2 web application is based on MVC pattern in order to facilitate unit test, without mocking pipeline asp.net, because it's very difficult. you don't have code on Code Behind in order to separate your code graphic and your code functional.With MVC your application become independent from view. you can replace easily technology of creating view.ASP.NET is a web platform. It provides a layer that sits on top of IIS (the web server) which facilitates the creation of web applications and web services. ASP.NET MVC is a framework specifically for building web applications. It sits ontop of ASP.NET and uses APIs provided by ASP.NET. ASP.NET Web Forms is another framework specifically for building web applications, and the new ASP.NET Web API is a platform for building web services.ASP.NET, at its most basic level, provides a means for you to provide general HTML markup combined with server side "controls" within the event-driven programming model that can be leveraged with VB, C#, and so on. You define the page(s) of a site, drop in the controls, and provide the programmatic plumbing to make it all work.ASP.NET MVC is an application framework based on the Model-View-Controller architectural pattern. This is what might be considered a "canned" framework for a specific way of implementing a web site, with a page acting as the "controller" and dispatching requests to the appropriate pages in the application. The idea is to "partition" the various elements of the application, eg business rules, presentation rules, etc.