Exchange 2013 debuted last year with the ability to configure a Hierarchical Address Book (HAB) for on premises deployments.
As many of our customers are migrating and evaluating the cloud, a consistent user experience between online and on premises deployments is not just a requirement, but an expectation. As such, we are really excited to announce the availability of HAB to Office 365 users, worldwide!
Read the full text of the announcement on the Exchange Team Blog.