Windows Server 2008 R2 Standard ( Microsoft Windows Server Version 6.1 Build 7601: Service Pack 1 )
IIS 7.5.7600.16385
In IIS Manager for a Site assigned an ApplicationPool with Identity = ApplicationPoolIdentity ( the default setting ) , how to determine the Windows account the site uses for directory operations ?  
In previous versions of IIS, Application Pools run under the Network Service account.
What is default account for ApplicationPoolIdentity ?
IIS Manager > Server Instance > Application Pools > Application Pool > right-click Set Application Pool Defaults... --OR-- Advanced Settings
both invoke the same dialog which contains an Identity field with ... button that allows setting the Identity -- no where does it specify what account is associated with ApplicationPoolIdentity or allow that value to be set
 
     
    