Visual Studio Help is available in two versions, Visual Studio Help 2008 and 2010, which are also known as MS Help 2.0 and MS Help 3.0, respectively. Originally, each of these help formats was announced as the upcoming the successor to HTML Help. However, in both cases Microsoft then backpedaled and it now seems clear that they are not going to be released as help formats for normal user applications.
Please note that the support for Visual Studio Help (both formats) is only included in the Professional and Server versions of Help+Manual. You cannot generate Visual Studio Help with the Basic version.
Visual Studio Help is only used for documenting components designed to be integrated into the Visual Studio .NET programming environment. The advantage of this is that the documentation becomes part of VS.NET's own documentation, making it possible to provide context-sensitive help for third-party VS.NET components.
For all other help applications you should always use one of the the other more appropriate formats, for example an HTML Help CHM file for help installed locally with your application and WebHelp for help accessed on a network or the Internet. For more information see Visual Studio Help in the More Advanced Procedures section.
Visual Studio Help (Advanced Procedures)
Visual Studio Help (Publishing Options)