.NET is the only framework introduced by MIcrosoft for Windows Apps. Its mostly use to develop large databases and web apps. .Net is highly flexible software which can consume code of any language in it and can work with any framework. Most importantly is a secure system which you can rely on. .NET family includes asp.net and ado.net, however LAMP, MVC, FCL (Framework Class Library) and CLR (Common Language Runtime) is also known as its supported framework. The usability of .NET for building mobile apps for Windows Smartphone is also commendable.