Smart tag/categorize emails in Outlook
This principle could be a game changer for email. Outlook search is really slow and manually sorting emails into folders is incredibly time consuming. So if emails could automatically have suggest categories assigned, you could speed up search and would only need to have four folders: Do, Schedule, Delegate, and Archive.
That could radically transform the way we do email, particularly for users that are receiving 100+ emails a day and struggling to keep inboxes in order.