Since last November and the introduction of the Clutter feature (see http://blogs.office.com/2014/11/11/de-clutter-inbox-office-365/ for more details), Microsoft has updated the Clutter feature to allow better management of this feature by administrators.
Now, administrators can define retention policies, define rules to bypass Clutter or personalize the message received by end-users.
See http://blogs.office.com/2015/03/03/making-clutter-office-365-even-better/ to know more