Thanks. I didn't know about X-Content-Type-Options! It is getting harder and harder to know all these headers nowadays. I am big fan of these checking tools with scores, it makes web developing entertaining. (A+! https://securityheaders.io/?q=https%3A%2F%2Fsatoshicrypt.com... )
Because its simple to manage, simple to install and that was my target. Its exclusively my choice, but hey its open source - take the code and create your own package...
I am often installing whole new email servers (author of https://poste.io here)... And thats not true, at least from my experience - well unless your first email is not "super promo whatever"...
I am making my living from administring linux/bsd boxes for small business or ISPs. I installed couple of full featured mailserver over time ...and i can tell, its not getting any better. It is strange area where technology moves much more slower and it is impossible to setup the full stack without bugs in first day for unskilled person. Even for me its not fun work to install and then maintain. (little self-promo here, i am trying to "start up" with http://poste.io )
You need users doing what most of them are not comfortable with. Photosharing is ok for everyone i guess. But if you will make app in which everyone draw on phone like Picasso it would be different story :)