Talk about all the AD-related roles in Windows Server 2008/R2.

Windows Server 2008 has five Active directory related roles. below are the list

•  Active Directory Domain Services (Identity): AD DS it provides the functionality of an identity and access (IDA) solution for enterprise networks. It also provides the mechanisms to support, manage, and configure resources in distribution network environments.
•  Active Directory Lightweight Directory Services (Applications): AD LDS formerly known as Active directory application mode (ADAM), provides support for directory-enabled applications.
• Active Directory Certificate Services (Trust): AD CS to set up a certificate authority for issuing digital certificates as a part of a public key infrastructure (PKI) that binds the identity of a person, device or service to corresponding private key. Certificates can be used to authenticate users and computers, provide web-based authentication, support smart card authentication, and support application, including secure wireless n/w, vpn, Ipsec, EFS, and more.
• Active Directory Rights management Services (Integrity): AD RMS is an information-protection technology that enables you to implement persistent usage policy templates (for documents) that define allowed and unauthorized use whether online, offline, inside, or outside the firewall.
• Active Directory Federation Services (Partnership): AD FS enable an organization to extend IDA across multiple platforms, including both window and non-windows environments, and to project identity and access rights across security boundaries to trusted partners.