Joe, most of our SM customers use a combo of Declude Hijack (available free from our website) and Throttling in SM. Declude Hijack prevents mass spam from leaving the server in the case of a compromised account. Please check out our KB article on how to handle an account that becomes compromised: http://know.mailsbestfriend.com/papers/Handling-Compromised-Accounts.shtml 99% of the time it is the user's computer that becomes compromised and the virus/malware uses their computer as an SMTP engine to send out spam, not a compromise of your server itself. Please let me know if you have any additional questions. Thanks.