The feature to have dashboards that report on stats for individual subaccounts, available at a glance, at an agency level.
For example, we offer email automation services and review systems for some of our clients - the ability to log into our agency dashboard, and see a view of all subaccounts that we offer a certain service for - for example email automation, and get reports on how many contacts were added to each subaccount, how many emails were sent, etc - in order to see which subaccounts are actively using the system, and which are not.
For example, it might be something like
X Electrical:
126 contacts added
357 emails sent
78% click rate
Y Plumbing:
34 contacts added
etc etc.
For agencies that offer different services, being able to see centralised reports on how these services are being used is crucial for us to be able to communicate with the client, and make recommendations if they have not been keeping up to date.