Microsoft has been testing Office 365's Clutter tool, which aims to highlight important messages in your inbox and move stuff you don't need to worry about immediately into folders, since late 2014. Apparently it's working well enough that from next month, it will be switched on for all Office 365 accounts by default.
In a blog post today, Microsoft said that Clutter will be enabled on all Office 365 accounts from June, though an exact date wasn't specified. Individual users will be able to switch off Clutter if they wish, and administrators can use PowerShell to help establish default policies (all new accounts will have Clutter, but you can ensure that this is switched off immediately after an account is created).
While Microsoft is proclaiming Clutter a success and says it is now moving more than 1 million emails a day, it is tweaking the way Clutter displays notifications. Users will now receive an alert the first time Clutter moves a new type of email, plus a weekly summary of what Clutter has handled.
De-cluttering everyone's inbox [Office Blogs]