One of the main purposes of OneDrive, aside from keeping all of a user's documents in a location where they can reach them no matter what machine they're accessing them from, is to share documents with other members of an organization or outside parties such as clients, vendors, and partners. Sometimes, however, an organization wants to lock this down and restrict who can share what and with who.
In the past, you'd have set these restrictions through SharePoint, but the new OneDrive admin center allows you to perform these tasks through a convenient specific interface:
The settings on this page actually apply to SharePoint ...