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!
Now, a tenant administrator for Office 365 is able to configure a HAB using the same commands one would in an on premises deployment.
Read more at source: http://blogs.technet.com/b/exchange/archive/2014/02/20/hierarchical-address-book-now-available-in-office-365-too.aspx