People Web Service
Provides classes that can be used to associate user identifiers (IDs) with security groups for SharePoint Foundation Web site permissions.
User IDs are validated against Active Directory Domain Services (AD°DS) as well as various role or membership providers. SPGroup security information may also be stored in a collection of cross-site groups for the site collection.
|PrincipalInfo||Contains information that represents the user of a SharePoint site.|
|SPPrincipalType||Specifies the scope and other information that is associated with a computer or user name that is maintained and authenticated by Active Directory Domain Services (AD DS).|