No, our mail server has never been compromised for spamming purposes. I'm well aware of how easy it is to misconfigure a mail server, and it's not that I think we are too smart or paranoid to have done so; it's just that in the years that we've been struggling with that problem, we've never discovered that misconfiguration, or discovered outgoing spam (other than bounces from e.g. kragen-tol-request.)

I hope I didn't come across as "hating on Google."