Email is hard because it is both architecturally insecure, and tremendously valuable to malicious attackers. It's hard because addressing its problems leads to

Email is hard because it is both architecturally insecure, and tremendously valuable to malicious attackers. It's hard because addressing its problems leads to buckets of different bad solutions rather than a single standard one. It's hard because the handful of big fish have decided that a reasonable way to combat its problems is to rely on interoperability with each other at the cost of you, the guy running mail. That said, as someone who does run mail, from my perspective it's more like the rest of the internet got easier and mail is still where it was a decade ago. Everything used to suck this much. With mail, the old hassles got addressed (goodbye sendmail and your m4 configuration nightmare) but got replaced with new hassles fast enough that it's kind of the same difference. But nowadays running the rest of your web stack (DNS, HTTP server, etc) is not very hard, though the cost of a DNS screwup is still huge.