With more and more services, integration and features available from Office 365 it can be become a little bit difficult to stay on top of what is being used through your Office 365 tenant.
Well, a new Your products section has appear below the Billing section of the Office 365 administration portal (https://admin.microsoft.com/)
From there you can have a comprehensive list of all subscriptions associated with your tenant (Subscriptions tab), third party applications (Apps tab), Azure or agreements (Benefits).
You then manage them directly from this blade.