.NET 4 includes a new version of the CLR, and a new .NET 4 specific machine.config file (which is installed side-by-side with the one used by .NET 2, .NET 3 and .NET 3.5).
The new .NET 4 machine.config file now automatically registers all of the ASP.NET tag sections, handlers and modules that we've added over the years, including the functionality for:
.ASP.NET Dynamic Data
.ASP.NET Routing (which can now be used for both ASP.NET WebForms and ASP.NET MVC)
.ASP.NET Chart Control (which now ships built-into ASP.NET V4)
What this means is that when you create a new "Empty ASP.NET application" project in VS 2010, you'll find that the new default application-level web.config file is now clean and simple:
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