Schooling A Sea of Phish Part 2: Enhanced Anti-spoofing technology in Office 365

It checks for similar displaynames and email addresses. "How" Microsoft is doing it, is probably proprietary information, but I can confirm it works. 

We have a legitimate spoofing case in our environment where the display is similar to ours, but the mail address is [email protected] and I get the spoofing notification. 

I also get notified when the endusers send messages from their personal email account (as in [email protected]) to the corporate account.