Terry Zink is one of Microsoft's best hires. He's the anti-spam czar for Microsoft Office 365, and writes a beautiful blog post covering what Microsoft does to stop outbound anti-spam and maintain a great reputation to get their clients' email delivered.
Of course, much of what Microsoft Office 365 do to stop outbound spam involved the usual tactics such as monitoring IP reputations and disabling account if they:
- Send too many emails that are then marked as spam
- Send too many emails in a short amount of time
Terry also mentions that the actual limits called out above are never publicly revealed so that spammers can never know the limitations of the mail that can be sent before it is marked as spam.
You can read the article here to find out more ways Microsoft Office 365 control outbound spam.