Why not offer to host the email accounts of those you contact most frequently? Probably most of them couldn't host their own email server, and if you've already gone to the effort to do so, you can help them increase their privacy as well.
Because running a mail server can be a pretty big responsibility, especially if you're letting others send mail from it. The more people using your server, the more important it will be to monitor for abuse and deal with abuse reports.
When I first set up my mail server I was pretty excited about being able to help everyone I know get their email away from Google, Hotmail etc. But once I had it running, I quickly realized that I didn't really want to give to very many people. Even if I trust all of my friends not to abuse, I cannot trust all of their computers.
