What is Multi-Targeting in .net?

In the previous version of Visual Studio, each Visual Studio release supports to a specific version of the .NET Framework. For example, VS 2002 only worked with .NET 1.0, VS 2003 only worked with .NET 1.1, and VS 2005 only worked with .NET 2.0.

Now with the major change in VS2008 is to support "Multi-Targeting "
Visual Studio 2008 is used to create projects that target .NET Framework version 2.0, 3.0, or 3.5. is what we call as "Multi-Targeting".