Since the introduction of .Net 4.0, Visual Studio 2012 has supported Web.Config transforms. That is you can publish a Web.Config file per solution configuration in Visual Studio. This is great if you are attempting to deploy to different environments that would require different settings such as Connection Strings or AppSettings. However, it is limited to only the Publish Feature. With this trick you can configure Visual Studio 2012 to perform the Transform with every build. This would allow you to run your local development environment against other configurations. One reason for wanting to do this might be to debug a data issue in a QA Environment.