http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnbda/html/tdlg_ch5.asp
"Note For a Microsoft Visual Basic® .NET project with an AssemblyVersion
set to "1.0.*", the assembly version is only updated the first time the
project is rebuilt within the Visual Studio .NET integrated development
environment (IDE). The version number remains constant for subsequent
rebuilds within the same instance of Visual Studio .NET. This does not
represent a problem because the assembly version is for information only in
assemblies that do not have a strong name. For strong named assemblies, you
should avoid the use of wild characters in the AssemblyVersion attribute, as
explained in the following section.
For C# projects with an AssemblyVersion set to "1.0.*", the assembly version
is updated every time the project is rebuilt."