Lack of documentation is becoming a problem for acceptance.

Most of the effort in the software business goes into the maintenance of code that already exists.

At the time the Sendmail program had a very poor reputation with respect to security, with four root vulnerabilities per year for two successive years.

Writing software that's safe even in the presence of bugs makes the challenge even more interesting.

I don't expect an overnight change of all desktops to what the US Military used to call B3 level security. And even that would not stop users from shooting themselves into the foot.

One bug in an SMTP server can open up the whole machine for intrusion.

Sure, but competition is good for the user.