From my experience, Microsoft strives to maintain an n-tier application standard where an application is comprised of multiple layers that perform specific functions, for example: presentation layer, business layer, data access layer are three general layers that just about every formally structured application contains. The presentation layer contains anything to do with displaying information to the screen and how it appears on the screen. The business layer is the middle man between the presentation layer and data access layer and transforms data from the data access layer in to useable information to be stored later or sent to an output device through the presentation layer. The data access layer does as its name implies, it allows the business layer to access data from a data source like MS SQL Server, XML, or another data source.
One of my favorite technologies that Microsoft has come out with recently is the .Net Framework. This framework allows developers to code an application in multiple languages and compiles them in to one intermediate language called the Common Language Runtime (CLR). This allows VB and C# developers to work seamlessly together as if they were working in the same project. The only real disadvantage to using the .Net Framework is that it only natively runs on Microsoft operating systems. However, Microsoft does control a majority of the operating systems currently installed on modern computers and servers, especially with personal home computers.
Given that the Microsoft .Net Framework is so flexible it is an ideal for business to develop applications around it as long as they wanted to commit to using Microsoft technologies and operating systems in the future.
I have been a professional developer for about 9+ years now and have seen the .net framework work flawlessly in just about every instance I have used it. In addition, I have used it to develop web applications, mobile phone applications, desktop applications, web service applications, and windows service applications to name a few.