Resources for understanding web.config essentials

Question

What are the best resources for understanding what's possible (or not possible) to achieve using web.config settings.

Wikipedia is really short on answers at this time and many of the sites I've browsed to only have one or two configurations referenced and explained.

Answer 1

Well, I guess you need this:

ASP.Net configuration. http://msdn.microsoft.com/en-us/library/aa719558(VS.71).aspx

Understand how machine.config and web.config settings are used by .Net

and this:

The schema http://msdn.microsoft.com/en-us/library/b5ysx397(VS.71).aspx

essentially all possible configuration sections listed. Click on each of them to learn more.