Office 365 Public Launch

Microsoft officially launched Office 365, its cloud-based productivity suite. Azure Active Directory served as the underlying identity and access management system for all Office 365 users and services from day one.

Significance

This launch provided Azure AD with its first massive real-world testing ground and a huge initial user base, proving its scalability and foundational capabilities as an enterprise cloud identity service. It cemented Azure AD's role as the identity backbone for Microsoft's cloud ambitions.