.NET

Microsoft's "dot net" (.NET) is a "software platform". It's a proprietary language-neutral environment for writing programs that easily and securely inter-operate. Rather than targeting a particular hardware/OS combination, programs instead target ".NET", and run wherever .NET is implemented. In this way, it is just like java. .NET is also the collective name given to various bits of software built upon the .NET platform. These are both products (Visual Studio.NET and Windows.NET Server, for instance) and services (such as Passport, HailStorm, and so on).

.NET uses XML in many instances, especially when complex data is transferred. It is a case of using what works best to accomplish some tasks. Other than this, it has very little to do with XML, despite the mounds of marketing that issue forth from Redmond which try to make .NET and XML seem synonymous.