Whether programmer or administrator, we're always looking for details on certain ASP.NET or IIS configuration settings, and sometimes we come up wanting because of lack of good documentation.
The IIS team released an impressive IIS 7 reference a couple nights ago. You can find it here: http://www.iis.net/configreference. This is a reference definitely worth bookmarking. You can take every IIS configuration item, click on it on the side and be provided with detailed information written directly from the IIS team. Robert McMurray has worked hard to survey the product team directly to obtain a wealth of detailed information about every configuration setting, and Pete Harris and others have been hard at work helping make this happen.
I used it yesterday already to refresh my memory about responseMode for httpErrors: http://www.iis.net/ConfigReference/system.webServer/httpErrors.
This reference is well worth bookmarking. It will come in handy.