In Visual Studio 2010, when you add a new project, it hard not to notice couple of things about the web.config files.
1) Web.config file is clean and lean 🙂 (Read about this in Scott Gu’s blog here)
2) Web.config has 2 files attached to it, Web.Debug.config and Web.Release.config (see image).
These are new features that I think that are very valuable for the deployment process, In the past I have used manual swaps a lot to manage environment specfic information in the web.config files. This new feature will let you create deployment environment specific (Dev, QA, UAT, Stage, Prod, etc.) Web.config files using simple to write transformations. You can find detailed information on how to do this in this article. (Link)