.NET Framework is a software framework developed by Microsoft. It is powerful, flexible, and can be adapted to a broad range of uses. Every .NET developer should be at least proficient either in using VB.NET or C#, or even better, both languages. The great .NET developer should be capable of handling many aspects of the application, including but not limited to performance, scalability, security, and testing. A fully knowledgeable .NET developer can use .NET to build a highly distributed web application, a sophisticated desktop application, or even a modern mobile application. Additional knowledge about Mono is a plus, as the combination of .NET and Mono allows for an even a wider range of platforms to be targeted.